Search Archive:
380 Views April 2017 COOP Data Uploaded

Link: https://mesonet.agron.iastate.edu/climodat/

The quality controlled Iowa COOP data for April 2017 has been uploaded to the IEM. These observations are kindly provided by Harry Hillaker, our state climatologist, who passes along these notes on the month:

General Summary. Iowa temperatures averaged 50.8° or 1.9° above normal while precipitation totaled 3.89 inches or 0.38 inches above normal.   This ranks as the 23rd warmest and 35th wettest April among 145 years of records.   A warmer April was last recorded in 2012 and a wetter one in 2013.   This was the 13th consecutive April with a statewide average precipitation amount in excess of the historical April average of 3.05 inches (1873-2016).

Temperatures. Warmer than usual weather prevailed for 16 of the first 20 days of the month, averaging 6.3° above normal.   However, cloudy, wet and cold weather prevailed late in the month, particularly for the final five days of April which averaged 11.6° cooler than normal.   Temperature extremes for the month varied from a high of 84° at Lamoni on the 19th to a low of 20° at Battle Creek on the morning of the 7th.   However, probably the most significant temperature event of the month was a hard freeze across most of the northern one-third of Iowa on the morning of the 28th.   Temperatures fell to 22° at Mason City and Spencer.   While freezes are not uncommon at this time of year in northern Iowa the mild weather prevailing for much of the late winter and early spring accelerated development of horticultural crops and may have left them more susceptible to freeze damage.   Meanwhile, a handful of locations in far southern and extreme eastern Iowa have not recorded a freeze since March 22.

Heating Degree Day Totals. Home heating requirements, as estimated by heating degree day totals, averaged 14% less than usual during April and 7% less than last year.   Heating requirements thus far this season (since July 1, 2016) are running 16% less than normal and 2% less than last season at this time.

Precipitation. April precipitation totals varied from 1.88 inches at Estherville to 7.85 inches at Chariton.   With a few exceptions, rain totals were below normal over most of northwest and west central Iowa, roughly north and west of a line from Council Bluffs to Ames to Forest City.   At Chariton a higher April precipitation total has been recorded only twice (1897 and 1991) among 123 years of data.

Severe Weather. There were three severe weather outbreaks during the month.   The most widespread event came on the evening of the 15th with severe weather, mostly in the form of large hail, reported from 28 counties with hail to baseball size in Black Hawk and Plymouth counties.   Another event on the night of the 9th generated severe weather reports from 15 counties, again mostly in the form of hail, with largest hail of 2.5 inches in diameter from Mitchell County.   Finally, one last event on the evening of the 19th brought severe weather reports, mostly high winds, to eight counties.

The following is the number of new daily records set at COOP sites based on data back to 1951.

                 2017______________________2016__________________
                 APR  MAR  FEB  JAN  DEC  NOV  OCT  SEP  AUG  JUL
Maximum High:      5   92  546   43   40  226  242  225   32   17
Minimum High:    122   22    0   36   44   21    8   15   53  224
Maximum Low:      43   43  154  367   70  125  184  338   83  131
Minimum Low:      12   42    0   23   99   15    6    4   14   82
Maximum Precip:   97   40   55  219  167   85  118  295  196  151

The following is a table summarizing how well the IEM daily data estimator is working in comparison to the quality controlled data.

                 2017                         2016             
                 APR   MAR   FEB   JAN   DEC   NOV   OCT   SEP   AUG
High Temp Bias  -0.3  -1.0  -0.9   0.2   0.3   0.2   0.1   0.1   0.1
High Temp STD    M     M     M     2.0   2.0   2.1   2.2   2.0   1.8
Low  Temp Bias  -0.3  -0.4  -0.2   0.0   0.1   0.0   0.2   0.1   0.1
Low  Temp STD    M     M     M     2.3   2.3   2.8   2.5   2.3   2.0
Precip    Bias   0.02  0.05  0.05  0.01 -0.02  0.00  0.00 -0.01 -0.01
Precip    STD    0.49  0.39  0.33  0.07  0.07  0.09  0.12  0.27  0.30

The standard deviations are missing this month due to some new code that is not behaving as I expected. Just haven't allocated time to figure out why yet, sorry.

281 Views March 2017 COOP Data Uploaded

Link: https://mesonet.agron.iastate.edu/climodat/

The quality controlled Iowa COOP data for March 2017 has been uploaded to the IEM. These observations are kindly provided by Harry Hillaker, our state climatologist, who passes along these notes on the month:

General Summary. Temperatures averaged 37.0° or 1.1° above normal while precipitation totaled 2.55 inches or 0.40 inches greater than normal. This ranks as the 37th warmest and 40th wettest March among 145 years of records. A wetter March was last recorded in 2009 and a warmer one in 2012.

Temperatures. As is typical of the early spring season, there were some dramatic temperature fluctuations during the early and mid-portion of the month. Temperatures fell to 7° at Cresco on the morning of the 3rd with afternoon highs three days later climbing to 80° at Little Sioux and Sioux City on the 6th. The month's largest temperature extremes came just four days apart with a low of -9° at Stanley, Spencer, Estherville and Forest City on the morning of the 15th while Sidney recorded an afternoon high of 84° on the afternoon of the 19th. The last week of the month, however, saw very little fluctuation in temperatures as persistent cloud cover and frequent rain kept temperatures in the forties and fifties for most of the period.

Heating Degree Day Totals. Home heating requirements, as estimated by heating degree day totals, averaged 22% greater than last March but 4% less than normal. Heating degree day totals thus far this heating season (since July 1, 2016) are running 2% less than last season at this time and 16% less than normal.

Precipitation. There were a pair of statewide precipitation events during the first one-half of the month with light snow falling over far northwest Iowa on the 6th and light to moderate rain elsewhere with a few scattered locations receiving almost an inch of rain. Snow fell statewide on the 12th-13th with a maximum of 10.4 inches recorded at the Waterloo Airport to only trace amounts along the Missouri border. Precipitation, nearly all in the form of rain, was frequent during the final eight days of the month with the largest event coming on the 29th-30th with a statewide average of 0.93 inches of rain. Monthly precipitation totals varied from 1.14 inches at Le Mars to 4.41 inches at De Witt. Below normal precipitation amounts were mostly confined to the north one-third of the state, a welcome break from the wetter than normal pattern that has dominated that area of Iowa for much of the time since last summer. Snowfall averaged 4.2 inches or 0.5 inches less than normal. This ranks as the 56th lowest March snow amount among 130 years of record. As has been the case all winter, very little snow fell across the far southern portion of the state during March.

Severe Weather. An unusually widespread severe storm outbreak for so early in the year came on the afternoon and evening of the 6th. Severe weather was reported from 63 of Iowa's 99 counties with 18 tornadoes reported by the National Weather Service including six of EF-2 intensity. This was a new record for most tornadoes reported in Iowa during March (old record 17 in 1990). Additionally, large hail was reported from nine northern Iowa counties during the day on the 23rd.

The following is the number of new daily records set at COOP sites based on data back to 1951.

                 2017_________________2016_______________________
                 MAR  FEB  JAN  DEC  NOV  OCT  SEP  AUG  JUL  JUN
Maximum High:     92  546   43   40  226  242  225   32   17  238
Minimum High:     22    0   36   44   21    8   15   53  224   17
Maximum Low:      43  154  367   70  125  184  338   83  131  196
Minimum Low:      42    0   23   99   15    6    4   14   82   42
Maximum Precip:   40   55  219  167   85  118  295  196  151   84

The following is a table summarizing how well the IEM daily data estimator is working in comparison to the quality controlled data.

                 2017                  2016                   
                 MAR   FEB   JAN   DEC   NOV   OCT   SEP   AUG   JUL
High Temp Bias  -1.0  -0.9   0.2   0.3   0.2   0.1   0.1   0.1   0.1
High Temp STD    M     M     2.0   2.0   2.1   2.2   2.0   1.8   1.9
Low  Temp Bias  -0.4  -0.2   0.0   0.1   0.0   0.2   0.1   0.1   0.2
Low  Temp STD    M     M     2.3   2.3   2.8   2.5   2.3   2.0   2.0
Precip    Bias   0.02  0.05  0.01 -0.02  0.00  0.00 -0.01 -0.01 -0.02
Precip    STD    0.49  0.33  0.07  0.07  0.09  0.12  0.27  0.30  0.29

The standard deviations are missing this month due to some new code that is not behaving as I expected. Just haven't allocated time to figure out why yet, sorry.

422 Views February COOP Data Uploaded

Link: https://mesonet.agron.iastate.edu/climodat/

The quality controlled Iowa COOP data for February 2017 has been uploaded to the IEM. These observations are kindly provided by Harry Hillaker, our state climatologist, who passes along these notes on the month:

General Summary. Temperatures averaged 33.8° or 9.8° above normal while precipitation averaged 1.01 inches or just 0.04 inches less than normal.   This ranks as the 3rd warmest and 72nd wettest February among 145 years of records.   Only 1954 and 1998 brought a warmer February than this year.

Temperatures. Temperatures averaged near seasonal norms for the first nine days of the month.   However, warmer than normal weather prevailed for all but one (25th) of the remaining days of February  with an exceptionally mild period from the 16th through the 22nd when temperatures averaged 23.7° above normal.   A look at the Iowa record books back to 1891 found 62 February dates when temperatures reached 70 degrees or higher somewhere in the state.   Prior to this year no single February brought more than four days of 70 degree weather (1930, 1981 and 1996) with the longest streak of 70° weather being three consecutive days in 1996 (24th-25th-26th).   However, this February brought eight days of 70° weather with seven of those coming consecutively from the 16th through the 22nd with one more on the last day of the month.   Ottumwa recorded the highest temperature of the month with a 79° reading on the 22nd.   This reading has been exceeded only three times previously in February in Iowa (82° at Sidney on 2/29/1972 and 80° at Clarinda and Mount Ayr on 2/24/1930).   Daily record high temperatures were recorded somewhere in the state every day from the 16th through the 22nd, primarily across the southeast one-half of the state, with Ottumwa setting or tying daily records on each of these seven days.   On the other extreme Little Sioux recorded the only subzero temperature of the month with a -3° reading on the morning of the 9th.

Heating Degree Day Totals. Home heating requirements, as estimated by heating degree day totals, averaged 25% less than normal and 19% less than last February.   Heating degree day totals thus far this winter season are running 17% less than normal and 5% less than last season through the end of February.   A warmer heating season was last recorded in the winter of 2001-2002.

Precipitation. There were only two measureable snow events during the month.   The first one on the 8th brought snow to about the southern two-thirds of the state with greatest amounts falling across west central and south central Iowa where Indianola picked up 6.1 inches.   The second, and much more intense event, brought snow to all of the state on the 23th-24th.   Heaviest snow fell across the northwest where 12.5 inches fell near West Bend and 12.0 inches at Algona.   An inch or less of snow fell across east central Iowa and the southern one-quarter of the state.   Wind gusts up to 48 mph brought blizzard conditions across about the northwest one-third of the state with this late month storm.   Monthly snow totals varied from only 0.3 inches at Manchester to 13.6 inches at Little Sioux.   A statewide average of 4.5 inches of snow fell during the month, 2.3 inches less than normal and the lowest February total since 2009.   This ranks as the 43rd lowest February snow total among 130 years of records.   There were also several rain events during the month with the largest coming on the 20th when rain fell statewide with totals of an inch or more falling over parts of north central and northeast Iowa.   Monthly precipitation totals varied from only 0.20 inches at Allerton where this was the driest February since 1970 to 2.78 inches at Nashua or more than 2.5 times their normal amount for February.

Severe Weather. Thunderstorms developed across eastern Iowa during the late afternoon of the 28th and brought one brief tornado in Clinton County and large hail reports from eleven east central and southeast Iowa counties.   Only two other February tornadoes have been recorded in Iowa (Feb. 1, 1922 at Monticello and Feb. 23, 1977 at Mason City).   Thunderstorms were also fairly widespread on the 6th-7th, 20th and 23rd-24th but with only a few very isolated large hail occurrences on the 7th and 20th.

Winter Summary. Temperatures over the three mid-winters months averaged 26.8° or 4.7° above normal while precipitation totaled 4.17 inches or 0.83 inches above normal.   This ranks as the 9th warmest and 31st wettest winter among 144 years of records.   Six of the top ten warmest winters have come within the past 20 years.

The following is the number of new daily records set at COOP sites based on data back to 1951.

                 2017____________2016____________________________
                 FEB  JAN  DEC  NOV  OCT  SEP  AUG  JUL  JUN  MAY
Maximum High:    546   43   40  226  242  225   32   17  238   65
Minimum High:      0   36   44   21    8   15   53  224   17   81
Maximum Low:     154  367   70  125  184  338   83  131  196   21
Minimum Low:       0   23   99   15    6    4   14   82   42   72
Maximum Precip:   55  219  167   85  118  295  196  151   84   92

The following is a table summarizing how well the IEM daily data estimator is working in comparison to the quality controlled data.

                 2017              2016                        
                 FEB   JAN   DEC   NOV   OCT   SEP   AUG   JUL   JUN 
High Temp Bias  -0.9   0.2   0.3   0.2   0.1   0.1   0.1   0.1   0.2
High Temp STD    M     2.0   2.0   2.1   2.2   2.0   1.8   1.9   2.1
Low  Temp Bias  -0.2   0.0   0.1   0.0   0.2   0.1   0.1   0.2   0.2
Low  Temp STD    M     2.3   2.3   2.8   2.5   2.3   2.0   2.0   2.3
Precip    Bias   0.05  0.01 -0.02  0.00  0.00 -0.01 -0.01 -0.02 -0.02
Precip    STD    0.33  0.07  0.07  0.09  0.12  0.27  0.30  0.29  0.25

The standard deviations are missing this month due to some new code that is not behaving as I expected. Will resolve prior to next month.

399 Views January COOP Data Uploaded

Link: https://mesonet.agron.iastate.edu/climodat/

The quality controlled Iowa COOP data for January 2017 has been uploaded to the IEM. These observations are kindly provided by Harry Hillaker, our state climatologist, who passes along these notes on the month:

General Summary. Temperatures averaged 23.9° or 4.5° above normal while precipitation totaled 1.61 inches or 0.69 inches above normal.   This ranks as the 28th warmest and 23rd wettest January among 145 years of records.   A warmer January was last recorded in 2012 and a wetter one in 1996.

Temperatures. Relatively mild air prevailed across Iowa for most of January.   There were only seven days (4th-8th and 12th-13th) averaging cooler than usual.   Lowest temperatures were -14° readings at Northwood, Postville and Cresco on the morning of the 6th and again at Cresco on the morning of the 8th.   Subzero temperatures were recorded only once during the second one-half of the month when Cresco registered -2° on the morning of the 30th.   Meanwhile daily maximum temperatures reached into the fifties four times (10th, 18th, 21st and 30th) with Shenandoah the warmest with a 58° reading on the afternoon of the 30th.

Heating Degree Day Totals. Home heating requirements, as estimated by heating degree day totals, averaged 10% less than last January and normal.   Thus far this heating season (since July 1) heating requirements are running 1% less than last season at this time and 15% less than normal.

Precipitation.Monthly precipitation totals were above normal at all but a handful of scattered locations during January.   January precipitation amounts varied from 0.62 inches at Rock Rapids to 2.89 inches at Waterloo (where this was the third wettest January among 133 years of records).   Much of this precipitation came in the form of rain.   Rain was widespread on the 2nd-3rd, 10th, 15th-16th, 19th and 20th-21st.   The most notable of these rain events was the mid-month storm which brought considerable freezing rain to all but the far southeast corner of Iowa.   A few southeast Iowa locations picked up more than one inch of rain during this storm while greatest ice accumulations of around one-quarter inch coated a wide band across southwest, central and northeast Iowa.   Unseasonably heavy rain of a half-inch or more also fell over parts of central and northeast Iowa on the 10th.   The only snow event of consequence was a large one on the 25th-26th.   Six inches or more of snow fell across all of northwest and north central Iowa with Mason City reporting the most snow with 15.0 inches.   This one storm accounted for nearly all of the January snow in Iowa with a handful of other events bringing light accumulations to fairly small areas scattered across the state.  Monthly snow totals varied from only a trace at Fairfield (their lowest January total since no snow fell in 1989) to 15.7 inches at Mason City.   A statewide average of 4.5 inches of snow fell during the month, 3.0 inches less than normal.   This ranks as the 31st lowest January snow total among 130 years of records with a lower January total recorded just last year (3.7 inches).

The following is the number of new daily records set at COOP sites based on data back to 1951.

                 2017_______2016_________________________________
                 JAN  DEC  NOV  OCT  SEP  AUG  JUL  JUN  MAY  APR
Maximum High:     43   40  226  242  225   32   17  238   65   84
Minimum High:     36   44   21    8   15   53  224   17   81   72
Maximum Low:     367   70  125  184  338   83  131  196   21   63
Minimum Low:      23   99   15    6    4   14   82   42   72   53
Maximum Precip:  219  167   85  118  295  196  151   84   92   72

The following is a table summarizing how well the IEM daily data estimator is working in comparison to the quality controlled data.

                 2017     2016                                
                 JAN   DEC   NOV   OCT   SEP   AUG   JUL   JUN   MAY
High Temp Bias   0.2   0.3   0.2   0.1   0.1   0.1   0.1   0.2  -0.1
High Temp STD    2.0   2.0   2.1   2.2   2.0   1.8   1.9   2.1   2.0
Low  Temp Bias   0.0   0.1   0.0   0.2   0.1   0.1   0.2   0.2   0.2
Low  Temp STD    2.3   2.3   2.8   2.5   2.3   2.0   2.0   2.3   2.5
Precip    Bias   0.01 -0.02  0.00  0.00 -0.01 -0.01 -0.02 -0.02  0.00
Precip    STD    0.07  0.07  0.09  0.12  0.27  0.30  0.29  0.25  0.17

619 Views December COOP Data Uploaded

Link: https://mesonet.agron.iastate.edu/climodat/

The quality controlled Iowa COOP data for December 2016 has been uploaded to the IEM. These observations are kindly provided by Harry Hillaker, our state climatologist, who passes along these notes on the month:

General Summary. Iowa temperatures averaged 22.7° or 0.2° below normal while precipitation totaled 1.55 inches or 0.21 inches greater than normal.   This ranks as the 67th coolest and 37th wettest December among 144 years of record.

Temperatures. The month began and ended with an extended period of warmer than normal weather while below normal temperatures prevailed each day from the 7th through the 19th.   The most noteworthy temperature event of the month was the cold weather on the 18th.   Morning low temperatures on the 18th varied from -8° at Keokuk to -29° at Rock Rapids.   The Rock Rapids reading was the lowest temperature recorded in Iowa since Elkader saw -30° on February 28, 2015 and was the lowest December temperature in the state since a -34° reading at Elkader on December 25, 2000.   Afternoon high temperatures were below zero across about the northeast one-third of Iowa on the 18th.   Meanwhile wind chill indices dropped as low as -46° at Estherville and Spencer on the morning of the 18th for the lowest wind chill readings in Iowa since -53° was registered at Estherville on January 2, 2010.   Soils began to freeze with the arrival of colder air on the 7th and quickly extended to about a foot beneath the surface by the 20th across much of central and southern Iowa where little or no snow cover existed.   However, warmer weather late in the month, plus a widespread Christmas Day rain, partially or completely thawed soils over southern Iowa by the end of the month.   The month’s highest temperature was recorded at Keokuk on Christmas night with a 60° reading.

Heating Degree Day Totals. Home heating requirements, as estimated by heating degree day totals averaged the same as normal but 32% more than seen during the very mild December of 2015.   Thus far this heating season (since July 1), heating requirements have averaged 18% less than normal but 6% more than last season at this time.

Precipitation. Precipitation was relatively frequent during the month, but with plenty of breaks between events.   The first widespread snow of the season arrived on the 3rd-4th with snow accumulating at all but a few far southern Iowa locations.   Heaviest snow fell over extreme eastern Iowa where the Davenport Airport recorded 10.2 inches.   Widespread snow also fell over all but far southern-southwestern Iowa on the 10th-11th with a few totals of six inches over the far north/northeast.   Snow also fell statewide on the 16th-17th with greatest amounts again over the north where a few locations picked up a half-foot or more.   Still another statewide snow event came on the 23rd and once again resulted in little, if any, accumulation over the south while 3 to 5 inches fell across the northeast corner of Iowa.   The last, and largest precipitation event of the month, came on Christmas Day and brought a statewide average of 0.63 inches of rain.   Thunder accompanied the rain over about the west two-thirds of Iowa with rain totals exceeding an inch in a few areas.   The rain, combined with frozen soil (which prevented rainwater from soaking into the ground), brought some minor flooding, especially over the south where some ice jams occurred as river ice broke up.   Monthly precipitation totals were generally well above normal across the northwest one-half of the state.   Precipitation totals varied from 0.82 inches at Sac City to 2.91 inches at Saint Ansgar.   Snowfall totals varied from only an inch at Allerton, Clarinda and Red Oak to 20.8 inches at Saint Ansgar.   The statewide average snowfall was 8.2 inches or 0.1 inches less than average.   This ranks as the 40th greatest December snowfall among 130 years of records.

General Summary. Temperatures averaged 50.6° or 2.5° above normal while precipitation totaled 38.78 inches or 3.51 inches above normal.   This ranks as the 5th warmest and 19th wettest year among 144 years of records.

Record 2016 precipitation totals are listed below:
Station2016 TotalPrevious Annual RecordPeriod of Record
Charles City58.5851.35 in 1999133 years
Decorah58.0848.74 in 2007128 years
Cresco57.5647.87 in 1951110 years
New Hampton57.1151.88 in 2007110 years
Osage53.1945.72 in 1999112 years
Lake Mills50.2147.35 in 199362 years
Mason City Airport7.7446.76 in 199174 years
Mason City46.3645.63 in 1990117 years


Severe Weather. Preliminary data from the National Weather Service indicates that 43 tornadoes touched down in Iowa in 2016, six fewer than the average of the previous 30 years.   Only two of these storms reached EF-2 strength, both in Benton County on July 17.

The following is the number of new daily records set at COOP sites based on data back to 1951.

                 _____2016_______________________________________
                 DEC  NOV  OCT  SEP  AUG  JUL  JUN  MAY  APR  MAR
Maximum High:     40  226  242  225   32   17  238   65   84  135
Minimum High:     44   21    8   15   53  224   17   81   72    5
Maximum Low:      70  125  184  338   83  131  196   21   63  268
Minimum Low:      99   15    6    4   14   82   42   72   53   10
Maximum Precip:  167   85  118  295  196  151   84   92   72  124

The following is a table summarizing how well the IEM daily data estimator is working in comparison to the quality controlled data.

                      2016                                    
                 DEC   NOV   OCT   SEP   AUG   JUL   JUN   MAY   APR
High Temp Bias   0.3   0.2   0.1   0.1   0.1   0.1   0.2  -0.1   0.2
High Temp STD    2.0   2.1   2.2   2.0   1.8   1.9   2.1   2.0   2.5
Low  Temp Bias   0.1   0.0   0.2   0.1   0.1   0.2   0.2   0.2   0.2
Low  Temp STD    2.3   2.8   2.5   2.3   2.0   2.0   2.3   2.5   2.4
Precip    Bias  -0.02  0.00  0.00 -0.01 -0.01 -0.02 -0.02  0.00  0.00
Precip    STD    0.07  0.09  0.12  0.27  0.30  0.29  0.25  0.17  0.11

640 Views November COOP Data Uploaded

Link: https://mesonet.agron.iastate.edu/climodat/

The quality controlled Iowa COOP data for November 2016 has been uploaded to the IEM. These observations are kindly provided by Harry Hillaker, our state climatologist, who passes along these notes on the month:

General Summary. Iowa temperatures averaged 44.9° or 8.3° above normal while precipitation totaled 1.45 inches or 0.60 inches less than normal.   This ranks as the second warmest and 66th driest November among 144 years of records.   The only warmer November came in 2001.

Temperatures. Above normal temperatures were the rule throughout the month as only three days (19th-21st) brought cooler than usual weather.    There were eleven days when temperatures reached or exceeded 70° during the month with Donnellson recording the highest temperature with an 81° reading on the 1st.   Daily record high temperatures were set at a few locations on the 17th when Donnellson, Mount Pleasant, Muscatine and Ottumwa reached 77°.   The growing season officially came to an end at the Keokuk Lock & Dam on the morning of the 19th when the temperature fell to 31°.   Only in 1944 (November 24) has a later first freeze occurred in Iowa (also at Keokuk Lock & Dam).   The coldest weather of the month came on the 20th and 21st when Battle Creek (20th), Rock Rapids (20th), Cresco (21st) and Elkader (21st) recorded 13° temperatures.

Heating Degree Day Totals. Home heating requirements, as estimated by heating degree day totals, averaged 30% less than normal and 13% less than last November.   Heating Degree Day totals thus far this heating season are running 17% less than last year at this time and 34% less than normal.

Precipitation. Precipitation totals during November were below normal over most of Iowa.   The exceptions were the far northwest and a small area near Dubuque.   Very dry weather prevailed over all of Iowa during the first three weeks of the month with a statewide average of only 0.23 inches of moisture while normal for the period is 1.51 inches.   The last nine days of November were much wetter thanks to widespread rain events on the 22nd-23rd and 27th.   Bellevue Lock and Dam recorded the most rain in November with 2.99 inches.    November precipitation totals were well below normal over most of southern Iowa where Seymour reported only 0.42 inches for the month.   At Albia monthly precipitation was below normal for the tenth time among the past eleven months and 2016 year-to-date rainfall is running 16 inches less than normal.    The first accumulating snow of the season occurred over far northwest Iowa on the 18th with Lester in Lyon County reporting the most snow with 4.5 inches.   This midmonth storm was accompanied by wind gusts as high as 55 mph.   Otherwise accumulating snow was minimal for the remainder of the month with only a few areas of northwestern Iowa seeing a dusting of snow on the 29th and 30th.   The statewide average snowfall for November was 0.2 inches, 2.5 inches less than normal.   This was the 11th lowest November snow total among 130 years of record.

Severe Weather. Severe thunderstorms made a late season return with at least five short-lived tornadoes touching down in central Iowa on the afternoon of the 28th.   Tornadoes have been recorded in Iowa later in the year only four times, the latest of which came on December 23 of last year.

Autumn Summary. Temperatures for the three fall months of September, October and November averaged 55.8° or 5.6° above normal while precipitation totaled 9.74 inches or 1.71 inches more than normal.   This ranks as the 2nd warmest and 27th wettest fall among 144 years of records.   Only 1931 brought a higher fall average temperature.   A higher fall precipitation total has occurred only once since 1992 and came just last year.   Despite the high autumn rain totals in 2015 and 2016 extended periods of dry weather in October and/or November in both years allowed harvest activities to be completed in a timely manner in most areas.

The following is the number of new daily records set at COOP sites based on data back to 1951.

                 _____2016_______________________________________
                 NOV  OCT  SEP  AUG  JUL  JUN  MAY  APR  MAR  FEB
Maximum High:    226  242  225   32   17  238   65   84  135  213
Minimum High:     21    8   15   53  224   17   81   72    5   59
Maximum Low:     125  184  338   83  131  196   21   63  268  159
Minimum Low:      15    6    4   14   82   42   72   53   10   19
Maximum Precip:   85  118  295  196  151   84   92   72  124  141

The following is a table summarizing how well the IEM daily data estimator is working in comparison to the quality controlled data.

                      2016                                    
                 NOV   OCT   SEP   AUG   JUL   JUN   MAY   APR   MAR
High Temp Bias   0.2   0.1   0.1   0.1   0.1   0.2  -0.1   0.2   0.4
High Temp STD    2.1   2.2   2.0   1.8   1.9   2.1   2.0   2.5   2.6
Low  Temp Bias   0.0   0.2   0.1   0.1   0.2   0.2   0.2   0.2   0.3
Low  Temp STD    2.8   2.5   2.3   2.0   2.0   2.3   2.5   2.4   2.7
Precip    Bias   0.00  0.00 -0.01 -0.01 -0.02 -0.02  0.00  0.00  0.00
Precip    STD    0.09  0.12  0.27  0.30  0.29  0.25  0.17  0.11  0.09

811 Views October COOP Data Uploaded

Link: https://mesonet.agron.iastate.edu/climodat/

The quality controlled Iowa COOP data for October 2016 has been uploaded to the IEM. These observations are kindly provided by Harry Hillaker, our state climatologist, who passes along these notes on the month:

General Summary. Iowa temperatures averaged 55.2° or 4.4° above normal while precipitation totaled 2.10 inches or 0.51 inches less than normal.   This ranks as the 23rd warmest and 70th driest October among 144 years of records.   A warmer October was last recorded in 2007.

Temperatures. Warmer than normal weather was the rule for most of October as only six days (7th-8th, 11th-12th and 20th-21st) during the month averaged cooler than usual.   Temperatures averaged ten or more degrees above normal on the 4th, 11th, 15th-17th and 28th-29th while the most abnormally cool day was the 13th at nine degrees below normal.   Burlington reported the highest temperature of the month with a 91° reading on the 17th when daily record high temperatures were recorded at numerous locations across the state.   Meanwhile, Iowa’s first freeze of the season was recorded at Little Sioux on the morning of the 7th.   The first hard freeze of the fall occurred over much of the northwest two-thirds of Iowa on the morning of the 13th with the lowest temperature recorded at Battle Creek with 23°.   However, by month’s end 10% of the state, mostly in far eastern and southeastern Iowa, had yet to see a temperature of 32° or lower.   Not since 1998 (32%) has more of the state entered November without a freeze.

Heating Degree Day Totals. Home heating requirements, as estimated by heating degree day totals, averaged 31% less than normal and 17% less than last year.   Thus far this heating season (since July 1) heating requirements are running 21% less than one year ago at this time and 39% less than normal.

Precipitation. A drier than normal weather pattern prevailed across most of Iowa during October.   Greater than normal rain totals were mostly confined to about the northern two or three tiers of counties.   Northeastern Iowa, which had been plagued with numerous heavy rain events in recent months finally got a break from the wet weather from the last week in September until October 25-26 when widespread rains of two to nearly three inches occurred.   October rainfall was less than one-half of normal over much of central and south central Iowa with ISU Agronomy Farm in eastern Boone County reporting the least rain at 0.47 inches.   Keokuk, thanks largely to a very isolated downpour of 4.98 inches of rain on the morning of the 5th, recorded the most rain during the month with 6.93 inches (however, the official Keokuk measurement site at the Lock & Dam partially missed this early month downpour and had a monthly rain total of 4.92 inches).   River flows at month’s end continue at well above seasonal normals along most of Iowa’s major rivers with below normal flows confined to smaller watersheds in south central Iowa.   While October precipitation was not excessive, it was enough to push the 2016 annual totals to new records at Osage and New Hampton.   These two locations join Charles City, Decorah and Cresco which surpassed their previous annual records in September.
Station2016 TotalPrevious Annual RecordPeriod of Record
Charles City54.82 inches51.35 in 1999 133 years
Decorah54.02 inches48.74 in 2007 128 years
Cresco53.51 inches47.87 in 1951 110 years
New Hampton53.14 inches51.88 in 2007110 years
Osage48.97 inches45.72 in 1999 112 years

The following is the number of new daily records set at COOP sites based on data back to 1951.

                 _____2016_______________________________________
                 OCT  SEP  AUG  JUL  JUN  MAY  APR  MAR  FEB  JAN
Maximum High:    242  225   32   17  238   65   84  135  213   29
Minimum High:      8   15   53  224   17   81   72    5   59   98
Maximum Low:     184  338   83  131  196   21   63  268  159   89
Minimum Low:       6    4   14   82   42   72   53   10   19   63
Maximum Precip:  118  295  196  151   84   92   72  124  141  156

The following is a table summarizing how well the IEM daily data estimator is working in comparison to the quality controlled data.

                      2016                                    
                 OCT   SEP   AUG   JUL   JUN   MAY   APR   MAR   FEB
High Temp Bias   0.1   0.1   0.1   0.1   0.2  -0.1   0.2   0.4   0.6
High Temp STD    2.2   2.0   1.8   1.9   2.1   2.0   2.5   2.6   2.4
Low  Temp Bias   0.2   0.1   0.1   0.2   0.2   0.2   0.2   0.3   0.2
Low  Temp STD    2.5   2.3   2.0   2.0   2.3   2.5   2.4   2.7   2.4
Precip    Bias   0.00 -0.01 -0.01 -0.02 -0.02  0.00  0.00  0.00  0.01
Precip    STD    0.12  0.27  0.30  0.29  0.25  0.17  0.11  0.09  0.07

797 Views September COOP Data Uploaded

Link: https://mesonet.agron.iastate.edu/climodat/

The quality controlled Iowa COOP data for September 2016 has been uploaded to the IEM. These observations are kindly provided by Harry Hillaker, our state climatologist, who passes along these notes on the month:

General Summary. Iowa temperatures averaged 67.3° or 4.1° above normal while precipitation totaled 6.19 inches or 2.81 inches above normal.   This ranks as the 15th warmest and 13th wettest September among 144 years of state records.   A wetter September last occurred in 1986 while a warmer one came just last year.

Temperatures. Above normal temperatures were the rule for most of the month with below normal readings confined to the 1st-3rd, 10th-11th, 13th and 28th.   There were six days averaging more than ten degrees above normal (6th and 20th through 24th) while the 2nd was the most unusually cool at just 3.7 degrees below normal.   Temperatures extremes varied from highs of 94° at Burlington on the 6th and at Algona, Atlantic, Clarion, Indianola and Sigourney on the 21st.   The lowest temperatures occurred at Spencer Airport on the mornings of the 29th and 30th with 38° readings, which was also matched at Sheldon on the 29th.   This was the highest statewide September minimum temperature on record (old record of 36° in 1905 and 1987).

Cooling Degree Days. Home air conditioning requirements, as estimated by cooling degree day totals, averaged 62% greater than normal but 24% less than last September.   Cooling degree day totals for the year-to-date are running 21% greater than last year and 17% greater than normal.

Precipitation. The big weather news for the month was the excessive rains over central and northern Iowa on the 9th-10th, 15th-16th and 21st-23rd.    The first of these three events brought rain statewide with Clarksville reporting the most rain with 4.35 inches.   The second event brought the most widespread heavy rains of the month with a maximum of 5.35 inches near Blencoe in Monona County.   However, the most destructive event was the final one.   This last event largely left the southern one-third of Iowa dry but dumped 10.56 inches of rain near Nora Springs and 9.44 inches near Nashua.   Major flooding occurred across much of north central and northeast Iowa and locations downstream of the heaviest rains.   The Shell Rock River at Shell Rock set a record flood crest 1.15 feet higher than the old record of June 2008.   Flooding along the Cedar River at Cedar Falls, Waterloo and Cedar Rapids was the second highest of record behind the disastrous floods of 2008.   Monthly rain totals of ten inches or more were fairly common across the north one-third of the state while parts of southeast Iowa were unusually dry.   Monthly rain totals varied from only 0.90 inches at Fairfield (less than one-third of normal) to 17.25 near Nora Springs.   A higher September rain total than that at Nora Springs has been recorded in only two other years in Iowa (1926 and 1970).   Record high September rain totals were set at the following locations:
StationSep 2016 TotalPrevious Sep RecordPeriod of Record
Charles City15.83 inches12.51 in 1965 134 years
Decorah11.6611.21 in 1972 134 years
Tripoli11.498.02 in 1965 69 years
New Hampton11.179.82 in 1965 115 years
Postville10.78 8.82 in 1931 75 years
Emmetsburg10.039.82 in 1964 75 years
Sheldon9.699.52 in 1926 106 years


September was the fourth consecutive very wet month across parts of northeastern Iowa.   As a result, with three months remaining in the year, record annual precipitation totals have already been established at the following locations:
Station2016 TotalPrevious Annual RecordPeriod of Record
Charles City51.93 inches51.35 in 1999 133 years
Decorah51.71 inches48.74 in 2007 128 years
Cresco50.90 inches47.87 in 1951 110 years
Osage45.98 inches45.72 in 1999 112 years

The following is the number of new daily records set at COOP sites based on data back to 1951.

                 _____2016________________________________2015___
                 SEP  AUG  JUL  JUN  MAY  APR  MAR  FEB  JAN  DEC
Maximum High:    225   32   17  238   65   84  135  213   29  244
Minimum High:     15   53  224   17   81   72    5   59   98   13
Maximum Low:     338   83  131  196   21   63  268  159   89  467
Minimum Low:       4   14   82   42   72   53   10   19   63    5
Maximum Precip:  295  196  151   84   92   72  124  141  156  439

The following is a table summarizing how well the IEM daily data estimator is working in comparison to the quality controlled data.

                      2016                                    
                 SEP   AUG   JUL   JUN   MAY   APR   MAR   FEB   JAN
High Temp Bias   0.1   0.1   0.1   0.2  -0.1   0.2   0.4   0.6   0.3
High Temp STD    2.0   1.8   1.9   2.1   2.0   2.5   2.6   2.4   2.1
Low  Temp Bias   0.1   0.1   0.2   0.2   0.2   0.2   0.3   0.2   0.2
Low  Temp STD    2.3   2.0   2.0   2.3   2.5   2.4   2.7   2.4   2.5
Precip    Bias  -0.01 -0.01 -0.02 -0.02  0.00  0.00  0.00  0.01 -0.01
Precip    STD    0.27  0.30  0.29  0.25  0.17  0.11  0.09  0.07  0.27

717 Views August COOP Data Uploaded

Link: https://mesonet.agron.iastate.edu/climodat/

The quality controlled Iowa COOP data for August 2016 has been uploaded to the IEM. These observations are kindly provided by Harry Hillaker, our state climatologist, who passes along these notes on the month:

General Summary. August temperatures averaged 72.3° or 0.8° above normal while precipitation totaled 6.05 inches or 1.85 inches above normal.   This ranks as the 58th warmest and 14th wettest August among 144 years of records.   A warmer August was last recorded in 2010 and a wetter one in 2007.

Temperatures. August temperatures fluctuated rather regularly throughout the month with no extended periods of either unusually warm or cool weather.   The hottest weather came on the 4th, 10th and 11th when actual temperatures reached into the mid-nineties and heat indices reached 110° or higher somewhere in the state each day.   As is typical as the day length slowly shortens during the month the lowest temperatures came during the second one-half of August with morning lows dipping into the forties in some locations on the 21st, 22nd and 26th.   Overall temperature extremes varied from a high of 97° at Lamoni on the afternoon of the 11th to lows of 46° on the morning of the 21st at Battle Creek, Sheldon and the Spencer Airport.

Cooling Degree Days. Home air conditioning requirements, as estimated by cooling degree day totals, averaged 44% more than last August and 9% greater than normal.   Thus far this year air conditioning requirements are running 13% more than normal and 33% greater than last year at this time.

Precipitation. Rain was frequent throughout the month and greater than normal over most of Iowa.   Below normal rain totals were mostly confined to far northwest Iowa and small areas of the west central and south central portions of the state.   The most widespread rains of the month came on the 11th-12th when a statewide average of 2.21 inches fell.   Greatest rains with this event fell along of the U.S. Highway 30 corridor from Boone County eastward to Clinton and Scott Counties with Swisher in Johnson County reporting a storm total of 7.05 inches.   However, the worst flooding of the month came as a result of a prolonged period of heavy rain over the night of the 23rd across far northeastern Iowa where a location five miles southeast of Decorah reported a storm total of 8.46 inches.   Record flood crests were established along some reaches of the Upper Iowa and Turkey Rivers on the 24th.   Monthly rain totals varied from 1.73 inches at Rock Rapids to 13.84 inches at Decorah.  This was the second highest August total among 131 years of records at Decorah (15.11 in 2007).

Summer Summary. Temperatures over the three summer months averaged 72.8° or 1.2° above normal while precipitation totaled 15.63 inches or 1.92 inches above normal.   This ranks as the 50th warmest and 20th wettest summer among 144 years of records.   This was the hottest summer since 2012.   Despite the high precipitation ranking this summer’s total was less than recorded during the past two summers.

The following is the number of new daily records set at COOP sites based on data back to 1951.

                 _____2016________________________________2015___
                 AUG  JUL  JUN  MAY  APR  MAR  FEB  JAN  DEC  NOV
Maximum High:     32   17  238   65   84  135  213   29  244   85
Minimum High:     53  224   17   81   72    5   59   98   13   56
Maximum Low:      83  131  196   21   63  268  159   89  467  171
Minimum Low:      14   82   42   72   53   10   19   63    5   58
Maximum Precip:  196  151   84   92   72  124  141  156  439  316

The following is a table summarizing how well the IEM daily data estimator is working in comparison to the quality controlled data.

                      2016                                    2015
                 AUG   JUL   JUN   MAY   APR   MAR   FEB   JAN   DEC
High Temp Bias   0.1   0.1   0.2  -0.1   0.2   0.4   0.6   0.3   0.2
High Temp STD    1.8   1.9   2.1   2.0   2.5   2.6   2.4   2.1   2.0
Low  Temp Bias   0.1   0.2   0.2   0.2   0.2   0.3   0.2   0.2   0.1
Low  Temp STD    2.0   2.0   2.3   2.5   2.4   2.7   2.4   2.5   2.2
Precip    Bias  -0.01 -0.02 -0.02  0.00  0.00  0.00  0.01 -0.01 -0.01
Precip    STD    0.30  0.29  0.25  0.17  0.11  0.09  0.07  0.27  0.14

491 Views July COOP Data Uploaded

Link: https://mesonet.agron.iastate.edu/climodat/

The quality controlled Iowa COOP data for July 2016 has been uploaded to the IEM. These observations are kindly provided by Harry Hillaker, our state climatologist, who passes along these notes on the month:

General Summary. Iowa temperatures averaged 73.0° or 0.6° below normal while precipitation totaled 5.88 inches or 1.38 inches above normal.   This ranks as the 50th coolest and 18th wettest July among 144 years of records.   This was the wettest July since 2010 and despite averaging slightly cooler than normal was the warmest July since 2012.

Temperatures. July began with much cooler than normal weather prevailing over the first four days of the month.   Cresco, Elkader and Estherville recorded the month’s lowest temperatures with 47° minimums on the morning of the 3rd.   Light rain and persistent cloud cover held the afternoon high temperature to only 61° at Fort Madison on the 3rd.   On the other end of the spectrum hotter than normal weather prevailed from the 17th through the 27th.   Actual temperatures peaked at 97° at Sioux City on the 20th and at Sioux City, Des Moines and Lamoni on the 21st.   However, very high humidity pushed heat index values (how hot the air ‘feels’ when humidity is taken into account) in excess of 110° somewhere in the state each day from the 20th through the 23rd.   The heat index reached 119° at Shenandoah at 5 p.m. on July 21 (95° actual temperature combined with a dew point of 82°).   Perry Airport reported the highest dew point temperature of the month at 85° at 7 p.m. on the 21st while the Charles City Airport reported 100% relative humidity at 9 p.m. that same evening with a temperature and dew point of 84°.   100% relative humidity at 84° represents twice as much water vapor in the air as does 100% relative humidity at 64° (a value that is close to the typical humidity level in Iowa during July).

Cooling Degree Days. Home air conditioning requirements, as estimated by cooling degree day totals, averaged 7% greater than last July but 5% less than normal.   Thus far this air conditioning season cooling degree day totals are running 29% greater than last year at this time and 14% greater than normal (the increase mostly results from a much warmer than usual June this year).

Precipitation. The relatively dry weather pattern that prevailed across much of Iowa during June continued into the first five days of July.   However, rainfall amounts and frequency increased dramatically from the 6th through the 20th when a statewide average of 4.83 inches of rain fell compared to the normal for this mid-July period of 2.23 inches.   The heaviest rain fell during the last five days of this period.   This abundant rain fell immediately prior to the hottest weather of the month and allowed crop conditions to actually improve slightly despite the heat.   Greatest July rain totals occurred over the southwest one-quarter of Iowa, as well along the Iowa-Minnesota border from Estherville eastward to Wisconsin.   However, rain amounts in far northwest Iowa were less than one-half of normal over much of Lyon, Sioux and Plymouth counties.   Monthly totals varied from 1.64 inches at Orange City to 12.37 inches at Red Oak.   Only 1958 brought more July rainfall (13.40 inches) to Red Oak among 105 years of records at that location.

Severe Weather. July brought reports of severe thunderstorms on fourteen dates with the most widespread severe weather occurring on the early morning of July 17 when a derecho brought a wide area of high winds from Lyon County on the South Dakota border to Scott County on the Illinois border with a peak recorded wind gust of 88 mph near Steamboat Rock.

The following is the number of new daily records set at COOP sites based on data back to 1951.

                 _____2016________________________________2015___
                 JUL  JUN  MAY  APR  MAR  FEB  JAN  DEC  NOV  OCT
Maximum High:     17  238   65   84  135  213   29  244   85   75
Minimum High:    224   17   81   72    5   59   98   13   56   21
Maximum Low:     131  196   21   63  268  159   89  467  171   79
Minimum Low:      82   42   72   53   10   19   63    5   58   20
Maximum Precip:  151   84   92   72  124  141  156  439  316  162

The following is a table summarizing how well the IEM daily data estimator is working in comparison to the quality controlled data.

                      2016                                2015
                 JUL   JUN   MAY   APR   MAR   FEB   JAN   DEC   NOV
High Temp Bias   0.1   0.2  -0.1   0.2   0.4   0.6   0.3   0.2   0.3
High Temp STD    1.9   2.1   2.0   2.5   2.6   2.4   2.1   2.0   2.2
Low  Temp Bias   0.2   0.2   0.2   0.2   0.3   0.2   0.2   0.1   0.2
Low  Temp STD    2.0   2.3   2.5   2.4   2.7   2.4   2.5   2.2   2.7
Precip    Bias  -0.02 -0.02  0.00  0.00  0.00  0.01 -0.01 -0.01 -0.00
Precip    STD    0.29  0.25  0.17  0.11  0.09  0.07  0.27  0.14  0.14

564 Views June COOP Data Uploaded

Link: https://mesonet.agron.iastate.edu/climodat/

The quality controlled Iowa COOP data for June 2016 has been uploaded to the IEM. These observations are kindly provided by Harry Hillaker, our state climatologist, who passes along these notes on the month:

General Summary. Iowa temperatures averaged 73.1° or 3.4° above normal while precipitation totaled 3.70 inches or 1.32 inches less than normal.   This ranks as the 15th warmest and 45th driest June among 144 years of record.   A warmer June was last recorded in 1991 and a drier one in 2012.

Temperatures. Warmer than normal weather was the rule through most of June.   While the daily statewide average temperature was slightly below normal on seven days during the month there was not a single day when every Iowa major reporting station was cooler than normal.   The warmth was most firmly established during the middle of the month with above normal temperatures throughout Iowa every day from the 9th through the 20th.   Little Sioux was the hot spot with a 100° maximum on the 11th.   This was Iowa’s first triple-digit reading since September 10, 2013.   This ended the second longest streak without 100° temperatures in Iowa at 1,004 consecutive days (record longest is 1,438 consecutive days from August 3, 1991 through July 9, 1995).   The relative lack of 100 degree temperatures in recent years is tied to frequent wetter than normal summers in Iowa.   The heat was most pronounced in southwestern Iowa where Little Sioux recorded 17 days with maximum temperatures of 90° or higher.   On the other extreme Allison, Anamosa, Dubuque, Elkader, Fayette, Forest City, New Hampton and Osage reached or exceeded 90 only once.   Belle Plaine, Elkader and Grinnell recorded the month’s lowest temperature with 43° readings on the morning of the 8th.

Cooling Degree Days. Home air conditioning requirements, as estimated by cooling degree day totals, averaged 59% greater than last June and 48% more than normal.   Thus far this air conditioning season cooling degree day totals are running 57% greater than last year at this time and 39% greater than normal.

Precipitation. June rain amounts were highly variable across Iowa.   Rainfall was much more frequent and came in greater amounts over about the northeast one-third of the state where monthly totals were as much as twice the June normal.   Cedar Falls reported the most rain with 11.22 inches while Salem in Henry County recorded only 0.25 inches.   At Donnellson in Lee County their June rain total of 0.53 inches is second only to 1991’s 0.45 inch total among 75 years of records.   At month’s end a large portion of south central and southeast Iowa was classified in ‘moderate drought’ by the U. S. Drought Monitor with an ‘abnormally dry’ designation for much of west central, central and southwest Iowa.

Severe Weather. As has been the case all year, severe weather was not as frequent or as widespread as typical across Iowa in June.   The most widespread event generated severe storm reports, mostly high winds, from 15 central and northern Iowa counties on the evening of the 14th.    However, the most damaging storms hit northwestern Iowa where a combination of hail and high winds resulted in considerable crop damage on the evening of the 17th.

The following is the number of new daily records set at COOP sites based on data back to 1951.

                 2016________________________________2015________
                 JUN  MAY  APR  MAR  FEB  JAN  DEC  NOV  OCT  SEP
Maximum High:    238   65   84  135  213   29  244   85   75  130
Minimum High:     17   81   72    5   59   98   13   56   21   13
Maximum Low:     196   21   63  268  159   89  467  171   79  336
Minimum Low:      42   72   53   10   19   63    5   58   20   25
Maximum Precip:   84   92   72  124  141  156  439  316  162  150

The following is a table summarizing how well the IEM daily data estimator is working in comparison to the quality controlled data.

                 2016                                2015
                 JUN   MAY   APR   MAR   FEB   JAN   DEC   NOV   OCT
High Temp Bias   0.2  -0.1   0.2   0.4   0.6   0.3   0.2   0.3   0.2
High Temp STD    2.1   2.0   2.5   2.6   2.4   2.1   2.0   2.2   1.8
Low  Temp Bias   0.2   0.2   0.2   0.3   0.2   0.2   0.1   0.2   0.1
Low  Temp STD    2.3   2.5   2.4   2.7   2.4   2.5   2.2   2.7   2.6
Precip    Bias  -0.02  0.00  0.00  0.00  0.01 -0.01 -0.01 -0.00 -0.01
Precip    STD    0.25  0.17  0.11  0.09  0.07  0.27  0.14  0.14  0.08

526 Views May COOP Data Uploaded

Link: https://mesonet.agron.iastate.edu/climodat/

The quality controlled Iowa COOP data for May 2016 has been uploaded to the IEM. These observations are kindly provided by Harry Hillaker, our state climatologist, who passes along these notes on the month:

General Summary. Iowa temperatures averaged 59.5° or 0.6° below normal while precipitation averaged 4.54 inches or 0.02 inches below normal.   This ranks as the 65th coolest and 53rd wettest May among 144 years of records.

Temperatures. The first five days of May brought below normal temperatures with a few locations reporting a light frost on the mornings of the 2nd, 3rd and 5th.   Above normal temperatures prevailed from the 6th through the 11th with Iowa’s first ninety degree readings of the year recorded at Marion, Guttenberg and Hawarden on the 6th.   Unseasonably cool weather was the rule at mid-month with below normal temperatures each day from the 12th through the 21st.   Freezes were reported in some areas on the 14th, 15th and 18th with the most widespread freeze centered upon northeast Iowa on the 15th when Cresco, Decorah and Elkader recorded 27° minimums.   Finally, the month finished with a string of ten consecutive warmer than normal days with the highest temperatures reported from Little Sioux and Lamoni at 89° on the 30th.

Heating Degree Days. Home heating requirements, as estimated by heating degree day totals, averaged 15% greater than last May and 8% more than normal.   However, heating requirements for the entire 2015-2016 season are running 15% less than last season at this time and 13% less than normal.

Precipitation. As with temperatures, there were alternating periods of below and above normal precipitation.   A wet period which began in late April continued into May 1.   Mostly dry weather prevailed from the 2nd through the 8th, especially across western Iowa where the second one-half of April had been very wet.   Wet weather returned from the 9th through the 13th, particularly across the west one-third of the state.   Mostly dry weather was the rule from the 14th through the 22nd while the remainder of the month brought frequent showers and thunderstorms.   Monthly precipitation amounts were well above normal across the northwest and southwest portions of Iowa while the driest weather occurred in central and south central Iowa, roughly along and just east of Interstate 35.   Monthly precipitation totals varied from 2.19 inches at Albia to 10.75 inches at Atlantic.  This was the second highest May rain total at Atlantic among 130 years of records at that location (May 1903 was wetter at 12.37 inches).   Excessively wet weather required some replanting of crops across western Iowa.   Nevertheless, for the state as a whole USDA NASS statistics indicate that planting progress and crop development are running a few days ahead of normal at month’s end.

Severe Weather. The relatively quiet start to the severe weather season this year continued through May.   There were a few isolated severe storms on the 9th, 11th and 13th.   Much more active weather came late in the month with severe thunderstorms reported somewhere in the state nearly every day between the 23rd and the 30th.   The most widespread severe weather event came on the night of the 25th when high winds, along with a few reports of large hail, were received from 20 counties scattered over the northern two-thirds of Iowa.

Spring Summary. Temperatures over the three spring months averaged 50.5° or 2.2° above normal while precipitation totaled 10.25 inches or 0.03 inches more than normal.   This ranks as the 26th warmest and 44th wettest spring among 144 years of state records.

The following is the number of new daily records set at COOP sites based on data back to 1951.

                 2016___________________________2015_____________
                 MAY  APR  MAR  FEB  JAN  DEC  NOV  OCT  SEP  AUG
Maximum High:     65   84  135  213   29  244   85   75  130   25
Minimum High:     81   72    5   59   98   13   56   21   13  269
Maximum Low:      21   63  268  159   89  467  171   79  336   38
Minimum Low:      72   53   10   19   63    5   58   20   25  156
Maximum Precip:   92   72  124  141  156  439  316  162  150  158

The following is a table summarizing how well the IEM daily data estimator is working in comparison to the quality controlled data.

                 2016                            2015
                 MAY   APR   MAR   FEB   JAN   DEC   NOV   OCT   SEP
High Temp Bias  -0.1   0.2   0.4   0.6   0.3   0.2   0.3   0.2   0.0
High Temp STD    2.0   2.5   2.6   2.4   2.1   2.0   2.2   1.8   1.7
Low  Temp Bias   0.2   0.2   0.3   0.2   0.2   0.1   0.2   0.1   0.0
Low  Temp STD    2.5   2.4   2.7   2.4   2.5   2.2   2.7   2.6   2.1
Precip    Bias   0.00  0.00  0.00  0.01 -0.01 -0.01 -0.00 -0.01  0.01
Precip    STD    0.17  0.11  0.09  0.07  0.27  0.14  0.14  0.08  0.26

713 Views April COOP Data Uploaded

Link: https://mesonet.agron.iastate.edu/climodat/

The quality controlled Iowa COOP data for April 2016 has been uploaded to the IEM. These observations are kindly provided by Harry Hillaker, our state climatologist, who passes along these notes on the month:

General Summary. Iowa temperatures averaged 49.9° or 1.0° above normal while precipitation totaled 3.25 inches or 0.26 inches less than normal.   This ranks as the 57th warmest and 56th wettest April among 144 years of records.

Temperatures. April opened and closed with mostly cooler than normal weather.   However, above normal temperatures prevailed every day from the 13th through the 26th.    The most noteworthy temperature events of the month were a pair of hard freezes on the 9th and 12th.   The 9th was the coldest day over most of the state with temperatures falling into the teens over much of the northwest two-thirds of Iowa.   The lowest temperature recorded on the 9th was 13° at Audubon while readings on the 12th fell to 16° at Sheldon, Spencer and Webster City.   There was some freeze injury to fruit trees, however, damage was not as great as feared given the advanced stage of development of vegetation which resulted from an extended period of very mild weather in March.   The month’s highest temperatures were 85° readings at Little Sioux on the 3rd and Donnellson on the 25th.   April came to an end with cloudy, cool and wet weather holding daytime highs down in the forties in many areas from the 27th through the 30th.

Heating Degree Days. Home heating requirements, as estimated by heating degree day totals, averaged 7% greater than last April, but 8% less than normal.   Degree day totals for the heating season-to-date (from July 1, 2015) are running 15% less than last season at this time and 14% less than normal.

Precipitation. Unseasonably dry weather prevailed for the first 18 days of the month when no measurable rain fell over parts of west central and southwest Iowa.   This dry period allowed an unusually early start to the corn planting season but for a time also delayed germination of specialty crops owing to dry topsoil.   Rainfall was much more frequent and plentiful for the final dozen days of April.   Late-month rainfall was particularly heavy over western Iowa where numerous rivers and streams reached or slightly exceeded flood stage.   The state-wide average precipitation averaged only 0.57 inches for the first 18 days of April but rebounded to 2.68 inches for the final 12 days of the month.   April precipitation totals were above normal over most of the western one-third of Iowa and driest over north central and northeast Iowa where monthly totals were under one-half of normal in some areas.   April rain totals varied from only 0.75 inches at Marquette to 7.52 inches at Alta.   At Guttenberg this was the driest April since 1942 while at Sioux City this was the wettest April since 1998.   Precipitation was widespread on the last day of the month.   However, much of this precipitation fell after the final rain measurements of the month ( made at 7 a.m. or 8 a.m. daily at most locations) and will be included in the May 2016 statistics.

Severe Weather. Severe thunderstorm activity was minimal during April and was limited to only the 24th and 27th.   High winds and hail were recorded within a narrow band of northwest Iowa on the 24th, roughly between Sioux City and Estherville.   There were also five short-lived tornadoes confirmed in southwest Iowa on the 27th, along with a few scattered hail reports.   However, April began with frequent non-thunderstorm high wind events with wind gusts of 40 mph or higher recorded on 8 of the first 9 days of the month (early April on average is the windiest time of the year in Iowa).

The following is the number of new daily records set at COOP sites based on data back to 1951.

                 2016______________________2015__________________
                 APR  MAR  FEB  JAN  DEC  NOV  OCT  SEP  AUG  JUL
Maximum High:     84  135  213   29  244   85   75  130   25   22
Minimum High:     72    5   59   98   13   56   21   13  269  261
Maximum Low:      63  268  159   89  467  171   79  336   38   54
Minimum Low:      53   10   19   63    5   58   20   25  156  139
Maximum Precip:   72  124  141  156  439  316  162  150  158  214

The following is a table summarizing how well the IEM daily data estimator is working in comparison to the quality controlled data.

                 2016                  2015
                 APR   MAR   FEB   JAN   DEC   NOV   OCT   SEP   AUG
High Temp Bias   0.2   0.4   0.6   0.3   0.2   0.3   0.2   0.0   0.1
High Temp STD    2.5   2.6   2.4   2.1   2.0   2.2   1.8   1.7   1.8
Low  Temp Bias   0.2   0.3   0.2   0.2   0.1   0.2   0.1   0.0   0.2
Low  Temp STD    2.4   2.7   2.4   2.5   2.2   2.7   2.6   2.1   2.1
Precip    Bias   0.00  0.00  0.01 -0.01 -0.01 -0.00 -0.01  0.01 -0.01
Precip    STD    0.11  0.09  0.07  0.27  0.14  0.14  0.08  0.26  0.27

947 Views March COOP Data Uploaded

Link: https://mesonet.agron.iastate.edu/climodat/

The quality controlled Iowa COOP data for March 2016 has been uploaded to the IEM. These observations are kindly provided by Harry Hillaker, our state climatologist, who passes along these notes on the month:

General Summary. Iowa temperatures averaged 42.0° or 6.1° above normal while precipitation totaled 2.46 inches or 0.31 inches above normal.   This ranks as the 13th warmest and 39th wettest March among 144 years of records.   A warmer March has been recorded only twice in the past 40 years (2000 and 2012) while a wetter one last came in 2009.

Temperatures. March began with three unseasonably cold days.   Rock Rapids and Sibley had daytime high temperatures of only 16° on the 1st while morning lows dipped to -6° at Elkader and Stanley on the 2nd.   However, above normal temperatures prevailed every day from the 4th through the 17th.   The warmest days were the 7th, 8th and 14th when temperatures averaged more than twenty degrees above normal.  Sioux City reported the month’s highest temperature with an 80° reading on the 7th.   While not a state record, this was the earliest occurrence of 80 degree weather at Sioux City (old record March 13, 2012).   Temperatures were much more seasonal for the final two weeks of the month, averaging 1.2° above normal.   Late month temperature extremes varied from a low of 9° at Spencer on the 25th to highs of 78° at Shenandoah and Sidney on the 30th.

Heating Degree Days. Home heating requirements, as estimated by heating degree day totals, averaged 18% less than last March and 22% less than normal.   Heating Degree Day totals thus far this heating season (since July 1, 2015) are running 17% less than last season at this time and 14% less than normal.   The last warmer heating season was 2011-2012.

Precipitation. Precipitation was frequent throughout the month with monthly totals about double March normal over parts of north central and northeast Iowa while some portions of southwest and south central Iowa saw less than one-half of normal.   March precipitation totals varied from 0.75 inches at Albia to 4.56 inches at Ionia.   The largest precipitation events came on the 14th-15th and 23rd-24th.   The first of these events brought rain statewide with a maximum of 1.50 inches falling at Ionia.   The second event brought very heavy snow to parts of northwest Iowa with 15.0 inches at Le Mars and 14.1 inches at Sioux City.   Snow also fell across the north one-half of the state on the first day of the month with six inches reported at Allison.   Monthly snow totals varied from only trace amounts for much southwest and south central Iowa to 17.0 inches at Algona.   The statewide average snowfall was 3.5 inches or 1.2 inches less than normal.   Virtually all of the state’s heavy snow events this winter have impacted northwest Iowa.   At Sheldon a total of 71.6 inches of snow has fallen this season, second only to a 73.7 inch total recorded at that location in the winter of 1961-1962.   Meanwhile parts of far southern Iowa have seen less than one-half the typical amount of snow this winter.

Severe Weather. March often marks the beginning of the severe thunderstorm season in Iowa and this month was no exception.   The first severe event of the season brought large hail to far southeast and east central Iowa on the evening of the 15th along with three confirmed tornadoes in Clinton County.   Additionally, there were a few reports of hail and high winds across southwest Iowa on the 23rd and hail over parts of west central and central Iowa on the 30th.

The following is the number of new daily records set at COOP sites based on data back to 1951.

                 2016________________2015________________________
                 MAR  FEB  JAN  DEC  NOV  OCT  SEP  AUG  JUL  JUN
Maximum High:    135  213   29  244   85   75  130   25   22   69
Minimum High:      5   59   98   13   56   21   13  269  261   88
Maximum Low:     268  159   89  467  171   79  336   38   54   32
Minimum Low:      10   19   63    5   58   20   25  156  139   26
Maximum Precip:  124  141  156  439  316  162  150  158  214  151

The following is a table summarizing how well the IEM daily data estimator is working in comparison to the quality controlled data.

                 2016                  2015
                 MAR   FEB   JAN   DEC   NOV   OCT   SEP   AUG   JUL
High Temp Bias   0.4   0.6   0.3   0.2   0.3   0.2   0.0   0.1   0.0
High Temp STD    2.6   2.4   2.1   2.0   2.2   1.8   1.7   1.8   1.7
Low  Temp Bias   0.3   0.2   0.2   0.1   0.2   0.1   0.0   0.2   0.2
Low  Temp STD    2.7   2.4   2.5   2.2   2.7   2.6   2.1   2.1   2.0
Precip    Bias   0.00  0.01 -0.01 -0.01 -0.00 -0.01  0.01 -0.01  0.00
Precip    STD    0.09  0.07  0.27  0.14  0.14  0.08  0.26  0.27  0.29

896 Views February COOP Data Uploaded

Link: https://mesonet.agron.iastate.edu/climodat/

The quality controlled Iowa COOP data for February 2016 has been uploaded to the IEM. These observations are kindly provided by Harry Hillaker, our state climatologist, who passes along these notes on the month:

General Summary. Iowa temperatures averaged 28.0° or 4.0° above normal while precipitation totaled 0.96 inches or 0.09 inches less than normal.   This ranks as the 33rd warmest and 69th driest February among 144 years of records.   Snowfall averaged 9.0 inches or 2.2 inches above normal to rank as the 37th snowiest February among 129 years of records.   This was the seventh consecutive snowier than normal February.

Temperatures. Bitter cold weather made a relatively brief appearance in Iowa during February with subzero temperatures reported on only the 4th, 5th and 10th through 13th.    Temperatures were above average every day from the 15th through the end of the month with only a handful of locations seeing readings dip below 20° during the second one-half of February.   Cresco reported the month’s lowest temperature with a -17° reading on the morning of the 13th.   Temperatures reached 73° at Shenandoah and Sidney on the 18th while Sidney reached 75° on the 27th.   These are the highest February temperatures recorded in Iowa since 1999 (76° at Glenwood on Feb. 10).   In response to the milder late-month weather soils began to thaw across central and southern Iowa on the 19th and were completely frost-free over about the southern one-half of Iowa at month’s end.   The late-month warmth also melted most of the snow cover that had persisted over northern Iowa since December 28.   Some flooding occurred in response to the snowmelt and ice jams that resulted from the break-up of river ice.

Heating Degree Days. Home heating requirements, as estimated by heating degree day totals, averaged 25% less than last February and 7% less than normal.   Season-to-date degree day totals are running 17% less than last season at this time and 13% less than normal.   The warmer weather and lower energy prices should result in considerably smaller heating bills this winter compared to recent years.

Precipitation. Over one-half of the month’s precipitation fell very early in the month with the major winter storm of the 2nd-3rd.   Heavy snow fell across the northwest one-half of Iowa with greatest amounts reported of 14.0 inches at Washta, 13.6 inches at Akron and 13.5 inches at Sheldon.   However, only a cold rain fell across extreme southeast Iowa with this storm.    There were very frequent light snow and/or rain events between the 3rd and 21st.   The largest of these events came on the 13th-14th when 2 to 4 inches of snow fell over much of the northeast one-half of the state.   However, winds gusts of 40 to 50 mph combined with light snowfall and deep snow cover left from the Groundhog Day storm system to create blizzard conditions over north central Iowa from the night of the 7th through the morning of the 9th.   Finally, winter weather made a return visit late on the 29th into March 1st with 2 to 5 inches of snow falling across the northern one-third of the state.   Overall monthly precipitation totals were well below normal over east central and southeast Iowa and well above normal over the northwest.   February precipitation totals varied from 0.20 inches at Williamsburg to 1.92 inches at Sheldon.  Monthly snowfall totals varied from only 1.3 inches at Clarinda to 23.4 inches at Sheldon.   Snow totals have been well above normal in three of the past four months in northwest Iowa.

Severe Weather. Wind gusts in the 50 to 60 mph range were common statewide on the 19th with Iowa City Airport reporting the highest gust at 63 mph.

Winter Summary. Temperatures over the three mid-winter months averaged 26.7° or 4.6° above normal while precipitation totaled 6.51 inches or nearly double the seasonal normal of 3.34 inches.   This ranks as the wettest and 17th warmest winter among 143 years of state records.   The last warmer winter came four years ago (2011-2012), averaging 1.2° warmer than this one.   Despite slightly below normal precipitation in January and February these two months brought enough precipitation when combined with December 2015’s record total to easily surpass the 6.00 inch total of the 1914-15 winter for the wettest on record.

The following is the number of new daily records set at COOP sites based on data back to 1951.

                 2016___________2015_____________________________
                 FEB  JAN  DEC  NOV  OCT  SEP  AUG  JUL  JUN  MAY
Maximum High:    213   29  244   85   75  130   25   22   69   28
Minimum High:     59   98   13   56   21   13  269  261   88  316
Maximum Low:     159   89  467  171   79  336   38   54   32   82
Minimum Low:      19   63    5   58   20   25  156  139   26   87
Maximum Precip:  141  156  439  316  162  150  158  214  151  155

The following is a table summarizing how well the IEM daily data estimator is working in comparison to the quality controlled data.

                 2016                  2015
                 FEB   JAN   DEC   NOV   OCT   SEP   AUG   JUL   JUN
High Temp Bias   0.6   0.3   0.2   0.3   0.2   0.0   0.1   0.0   0.0
High Temp STD    2.4   2.1   2.0   2.2   1.8   1.7   1.8   1.7   1.7
Low  Temp Bias   0.2   0.2   0.1   0.2   0.1   0.0   0.2   0.2   0.2
Low  Temp STD    2.4   2.5   2.2   2.7   2.6   2.1   2.1   2.0   2.0
Precip    Bias   0.01 -0.01 -0.01 -0.00 -0.01  0.01 -0.01  0.00  0.00
Precip    STD    0.07  0.27  0.14  0.14  0.08  0.26  0.27  0.29  0.33

1121 Views January COOP Data Uploaded

Link: https://mesonet.agron.iastate.edu/climodat/

The quality controlled Iowa COOP data for January 2016 has been uploaded to the IEM. These observations are kindly provided by Harry Hillaker, our state climatologist, who passes along these notes on the month:

General Summary. Iowa temperatures averaged 19.3° or 0.1° below normal while precipitation totaled 0.64 inches or 0.28inches below normal.   This ranks as the 69th warmest and 37th driest January among 144 years of records.

Temperatures. The new year opened with eight consecutive days of above normal temperatures, continuing the mild pattern that persisted through the last one-third of 2015.   A brief period of cold weather prevailed from the 9th through the 13th.   Daytime high temperatures reached only -4° at Elkader and Northwood on the 10th while morning lows fell to -18° at Spencer on the 10th and at Northwood on the 11th.   Brisk winds combined with the cold air to produce wind chill indices down to -36° at Estherville and Spencer on the morning of the 10th.   A brief warm-up occurred on the 14th and 15th with Lamoni recording the month’s highest temperature with a 56° reading on the 14th.   This was soon followed by the coldest weather of January on the 17th and 18th.   Spencer recorded a minimum temperature of -21° on the morning of the 17th along with a wind chill index of -42°.   Daytime highs remained below zero over about the northern one-half of the state on the 17th with Northwood reaching a maximum of only -9°.   Parts of far northeast and far northern Iowa endured a second straight day of subzero high temperatures on the 18th.   Temperatures were above normal in most areas from the 21st through the end of the month with no subzero readings recorded in the state after the 20th.   Temperatures reached into the low fifties at many far southern Iowa locations on the 29th, 30th and 31st.   The mild and wet December 2015 weather resulted in little, if any, soil frost at the beginning of January.   However, the arrival of very cold weather on the 9th quickly drove frost much deeper into the soil during the middle one-third of the month.   At month’s end soils were frozen to depths of 12 to 18 inches over central Iowa and to about ten inches across the southern part of the state.   However, a deeper snow pack across northern Iowa insulated the soils there with eight inches or less of frozen ground at month’s end.

Heating Degree Days. Home heating requirements, as estimated by heating degree day totals, averaged the same as normal, but 5% more than last January.   Thus far this heating season (since July 1) heating requirements are running 14% less than last year at this time and 15% less than normal.

Precipitation. Precipitation was frequent during January, but in sharp contrast to November and December did not amount to much.  About two-thirds of the month’s precipitation came in the form of rain from the 6th to the 9th.   Otherwise there were numerous light accumulations of snow through the remainder of January but only one event, on the 19th, brought more than four inches of snow to any single location when Mount Ayr accumulated 5.1 inches.   Despite the relative lack of new snowfall or persistent cold during January snow remained on the ground for most of the month across the northern one-half of the state.   The statewide average snowfall was 3.7 inches or 4.0 inches less than normal.   This ranks as the 19th least snowy January among 129 years of records.   January precipitation totals varied from 0.22 inches at Rock Rapids to 1.31 inches at Nashua.   Meanwhile monthly snowfall totals varied from 1.1 inches at Iowa City to 8.9 inches at Little Sioux.

The following is the number of new daily records set at COOP sites based on data back to 1951.

                 2016___________2015_____________________________
                 JAN  DEC  NOV  OCT  SEP  AUG  JUL  JUN  MAY  APR
Maximum High:     29  244   85   75  130   25   22   69   28   34
Minimum High:     98   13   56   21   13  269  261   88  316   28
Maximum Low:      89  467  171   79  336   38   54   32   82   34
Minimum Low:      63    5   58   20   25  156  139   26   87   76
Maximum Precip:  156  439  316  162  150  158  214  151  155  122

The following is a table summarizing how well the IEM daily data estimator is working in comparison to the quality controlled data.

                 2016         2015
                 JAN   DEC   NOV   OCT   SEP   AUG   JUL   JUN   MAY
High Temp Bias   0.3   0.2   0.3   0.2   0.0   0.1   0.0   0.0  -0.1
High Temp STD    2.1   2.0   2.2   1.8   1.7   1.8   1.7   1.7   2.5
Low  Temp Bias   0.2   0.1   0.2   0.1   0.0   0.2   0.2   0.2   0.1
Low  Temp STD    2.5   2.2   2.7   2.6   2.1   2.1   2.0   2.0   2.0
Precip    Bias  -0.01 -0.01 -0.00 -0.01  0.01 -0.01  0.00  0.00 -0.01
Precip    STD    0.27  0.14  0.14  0.08  0.26  0.27  0.29  0.33  0.20

1546 Views December COOP Data Uploaded

Link: https://mesonet.agron.iastate.edu/climodat/

The quality controlled Iowa COOP data for December 2015 has been uploaded to the IEM. These observations are kindly provided by Harry Hillaker, our state climatologist, who passes along these notes on the month:

General Summary. Temperatures averaged 32.9° or 10.0° above normal while precipitation totaled 4.90 inches or 3.56 inches above normal. This ranks as the wettest and 7th warmest December among 143 years of records. The previous wettest December was recorded in 1982 with 3.43 inches. The last warmer December was recorded in 1965.

Temperatures. Unseasonably warm weather was the rule through nearly all of December. Only one day (the 31st) brought a statewide average temperature that was below normal. This warm pattern began on August 31 with only 25 of the last 123 days of 2015 averaging below normal. The final one-third of the year averaged 5.6° above normal. Only 1931 was warmer for this late year period (when September, November and December all ranked in the top 5 warmest for their respective months). Temperature extremes for the month ranged from highs of 64° at Donnellson and Keokuk on the 12th, Bloomfield and Keosauqua on the 13th and Keosauqua again on the 23rd while Sheldon, Sioux Center and Spencer recorded the lowest temperatures with -6° readings on the morning of the 31st. There were five days (10th, 12th, 13th, 14th and 23rd) during the month when temperatures exceeded 60° somewhere in the state while only two days (3rd and 31st) brought sub-zero readings.

Heating Degree Days. Home heating requirements, as estimated by heating degree day totals, averaged 24% less than normal and 13% less than last December. Heating degree day totals so far this season (since July 1) are running 23% less than last year and 22% below normal.

Precipitation. A storm system brought heavy snow to far northwest Iowa on the last day of November with light rain and snow persisting over much of Iowa into the first two days of December. There was a welcome mostly dry period from the 3rd through the 11th. However, an unseasonably warm and humid air mass brought widespread heavy rainfall from the evening of the 12th through the morning of the 14th. An amazing statewide average of 2.82 inches of rain fell during this event. Only three winter months (December 1982, February 1881 and February 1915) have brought more precipitation to Iowa than this one storm system. Grundy Center recorded 5.98 inches of rain during this storm which easily exceeded their December monthly record precipitation total of 3.74 inches. Another storm system brought widespread rain on the 23rd with some central and northeast Iowa locations receiving over an inch of rain. The extended period of unseasonably warm and wet weather appeared to make a White Christmas impossible. However, a compact Christmas Eve storm system brought snow from southwest, through central and into northeast Iowa. Heavy snow fell from Council Bluffs to Ames with 14 inches reported at Persia is Harrison County. Finally, another large storm system brought heavy winter precipitation to much of Iowa on the 28th into the morning of the 29th. Heavy snow fell across the northern one-third of Iowa where 6 to 10 inch amounts were common. Meanwhile copious amounts of sleet and freezing rain fell over much of east central and southeast Iowa. Monthly precipitation totals (rain plus the liquid equivalent of snow and sleet) varied from 1.72 inches at Rock Rapids to 8.20 inches at Grundy Center. Grundy Center's total has been exceeded only once in Iowa during December when Keokuk recorded 8.56 inches in 1873. Dozens of cities set records for greatest December precipitation totals with a partial list below. Cherokee, Shenandoah and Storm Lake set record maximum totals for both November and December. Only two locations, Rock Rapids and Fort Madison failed to record at least double their normal December precipitation total.

CityDec. 2015 (inches)Previous Dec. Record Period of Record
Grundy Center8.203.74 in 1982123 years
Denison7.153.43 in 1984120 years
Glenwood6.744.19 in 1984127 years
Atlantic6.623.54 in 1982126 years
Clarinda6.164.73 in 1913132 years
Carroll6.093.88 in 1931128 years
Waterloo5.923.77 in 1982132 years
Logan5.804.76 in 1984146 years
Marshalltown5.603.41 in 1982134 years
Iowa Falls5.604.47 in 1982131 years
Oskaloosa5.524.16 in 2007137 years
Belle Plaine5.493.31 in 2007126 years
Dakota City5.463.72 in 2009129 years
Des Moines5.443.72 in 1931140 years
Sac City5.424.40 in 1871140 years
Indianola5.193.90 in 2009129 years
Decorah4.793.29 in 2010129 years
Storm Lake4.712.46 in 1931126 years
Cedar Rapids4.493.84 in 1982133 years
Charles City4.423.59 in 1891134 years
Mason City4.223.26 in 1982117 years
Ottumwa4.033.95 in 1895125 years

December snow totals varied from only 0.4 inches at Fort Madison to 24.9 inches at Rock Rapids. The statewide average snowfall was 9.8 inches or 1.5 inches above normal and ranks as the 29th highest December total among 129 years of records.

The following is the number of new daily records set at COOP sites based on data back to 1951.

                 __________2015__________________________________
                 DEC  NOV  OCT  SEP  AUG  JUL  JUN  MAY  APR  MAR
Maximum High:    244   85   75  130   25   22   69   28   34  182
Minimum High:     13   56   21   13  269  261   88  316   28  102
Maximum Low:     467  171   79  336   38   54   32   82   34   29
Minimum Low:       5   58   20   25  156  139   26   87   76   98
Maximum Precip:  439  316  162  150  158  214  151  155  122   17

The following is a table summarizing how well the IEM daily data estimator is working in comparison to the quality controlled data.

                      2015
                 DEC   NOV   OCT   SEP   AUG   JUL   JUN   MAY   APR
High Temp Bias   0.2   0.3   0.2   0.0   0.1   0.0   0.0  -0.1   0.0
High Temp STD    2.0   2.2   1.8   1.7   1.8   1.7   1.7   2.5   2.2
Low  Temp Bias   0.1   0.2   0.1   0.0   0.2   0.2   0.2   0.1   0.3
Low  Temp STD    2.2   2.7   2.6   2.1   2.1   2.0   2.0   2.0   2.7
Precip    Bias  -0.01 -0.00 -0.01  0.01 -0.01  0.00  0.00 -0.01  0.00
Precip    STD    0.14  0.14  0.08  0.26  0.27  0.29  0.33  0.20  0.13

1343 Views November COOP Data Uploaded

Link: https://mesonet.agron.iastate.edu/climodat/

The quality controlled Iowa COOP data for November 2015 has been uploaded to the IEM. These observations are kindly provided by Harry Hillaker, our state climatologist, who passes along these notes on the month:

General Summary. Temperatures averaged 41.8° or 5.2° above normal while precipitation totaled 4.23 inches or 2.18 inches above normal.   This ranks as the 10th warmest and 7th wettest November among 143 years of Iowa records.   A warmer November was last recorded in 2009 and a wetter one in 1992.

Temperatures. Temperatures were above normal during all of the first 19 days of the month, averaging 8.5 degrees above normal for the period.   Much more seasonal temperatures prevailed for the remainder of the month with readings averaging 0.7 degrees below normal for the final 11 days of November.   Daytime highs reached into the mid-seventies somewhere in the state on each of the first five days of the month with Des Moines, Glenwood and Shenandoah recording the highest temperatures of the month with 79° readings on the 2nd.   At the Des Moines Airport the first freeze (32°) of the season was finally recorded on the morning of the 13th.   This was the latest ‘first’ freeze among 138 years of records at Des Moines (old record November 11, 1882).   However, the Des Moines Airport freeze date was not representative of the state as a whole as only two other official measurement points recorded their first freeze of the 2015 fall season in November (the others were NWS-Johnston on Nov. 7 and Keokuk Lock & Dam on Nov.9).   The statewide record for latest first freeze was set in Keokuk on November 24, 1944.   Very cold weather did arrive following the major snowstorm of the 20th with Spencer Airport recording a low of -4° on the morning of the 21st while Waterloo Airport and Stanley recorded lows of -5° on the night of the 21st.

Heating Degree Days. Home heating requirements, as estimated by heating degree day totals, averaged 35% less than last November (which was the 4th coldest November on record) and 19% less than normal.   Heating degree day totals so far this heating season are running 30% less than last year at this time and 21% less than normal.

Precipitation. November began with relatively dry weather until Veteran’s Day when the first of a parade of five storm systems brought widespread precipitation to Iowa.   The Veteran’s Day event saw thunderstorms develop statewide with unseasonably heavy rain over far northwest Iowa and high winds and tornadoes over southern Iowa.   The tail-end of this first storm system also brought the state’s first accumulating snow to portions of west central Iowa.   Additional storm systems came through at about four day intervals on the 16th-18th, 20th-21st, 25th-27th and 29th-30th.   The most widespread rain came with storm #2 on the 16th-18th with a statewide average of 1.31 inches of rain.   The third storm was noteworthy owing to the heavy snow that fell across much of the state.   More than ten inches of snow fell across a wide area of northern Iowa with 15 inches reported at Rock Rapids and 16 inches near Kesley.   This event brought Iowa’s most widespread heavy snowfall for so early in the winter season since November 17-18, 1957.   The fourth storm system brought light snow to northwest Iowa and 1.5 to 2.5 inches of rain to the southeast one-third of the state.   Finally, the last storm brought heavy snow to northwest Iowa with 10 inches reported at Everly and Lake Park and one-half to an inch of rain elsewhere.   Much of the snow on November 30 fell after the final measurements for the month (the daily measurements are made at 7 or 8 a.m. at most locations), thus will be included in the December totals.   Monthly precipitation totals were above normal at all reporting points and varied from 2.63 inches at Zearing to 7.56 inches at Eldridge.   Record maximum precipitation totals for November were set at several locations:

StationNov 2015Old November RecordPeriod of Record
Sanborn6.14 inches4.96 in 1991104 years
Primghar5.87 inches4.16 in 198383 years
Rock Rapids5.62 inches4.77 in 1975113 years
Storm Lake5.57 inches4.20 in 1983124 years
Spencer5.48 inches4.51 in 1896103 years
Sheldon5.37 inches5.05 in 1909104 years
Cherokee4.93 inches4.54 in 198394 years
Shenandoah4.62 inches4.49 in 198383 years
Sibley4.59 inches4.24 in 1905116 years
Sioux City4.55 inches4.41 in 1922134 years

Monthly snow totals varied from only trace amounts at several far southwest Iowa locations to 22.4 inches at Spencer.   The statewide average snowfall was 6.3 inches or 3.6 inches above normal.   This is the 13th highest November snow total among 129 years of record and the highest for the month since 1991.

Severe Weather. The National Weather Service reported a total of 19 tornadoes across southern Iowa on Veteran’s Day with damaging winds reported from 51 counties, mostly in central and southern Iowa.   The tornado total exceeds the previous November record of 12 set on November 12, 2005.

Fall Summary. Temperatures for the three fall months of September, October and November averaged 54.4° or 4.2° above normal while precipitation totaled 10.14 inches or 2.11 inches above normal.   This ranks as the 6th warmest and 22nd wettest fall among 143 years of records.   A warmer fall was last recorded in 1963 and a wetter one in 1992.

The following is the number of new daily records set at COOP sites based on data back to 1951.

                 __________2015__________________________________
                 NOV  OCT  SEP  AUG  JUL  JUN  MAY  APR  MAR  FEB
Maximum High:     85   75  130   25   22   69   28   34  182   13
Minimum High:     56   21   13  269  261   88  316   28  102  364
Maximum Low:     171   79  336   38   54   32   82   34   29   25
Minimum Low:      58   20   25  156  139   26   87   76   98  345
Maximum Precip:  316  162  150  158  214  151  155  122   17  113

The following is a table summarizing how well the IEM daily data estimator is working in comparison to the quality controlled data.

                      2015
                 NOV   OCT   SEP   AUG   JUL   JUN   MAY   APR   MAR
High Temp Bias   0.3   0.2   0.0   0.1   0.0   0.0  -0.1   0.0   0.3
High Temp STD    2.2   1.8   1.7   1.8   1.7   1.7   2.5   2.2   2.6
Low  Temp Bias   0.2   0.1   0.0   0.2   0.2   0.2   0.1   0.3   0.4
Low  Temp STD    2.7   2.6   2.1   2.1   2.0   2.0   2.0   2.7   2.9
Precip    Bias  -0.00 -0.01  0.01 -0.01  0.00  0.00 -0.01  0.00  0.01
Precip    STD    0.14  0.08  0.26  0.27  0.29  0.33  0.20  0.13  0.13

1198 Views October COOP Data Uploaded

Link: https://mesonet.agron.iastate.edu/climodat/

The quality controlled Iowa COOP data for October 2015 has been uploaded to the IEM. These observations are kindly provided by Harry Hillaker, our state climatologist, who passes along these notes on the month:

General Summary. Iowa temperatures averaged 53.0° or 2.2° above normal while precipitation totaled 1.78 inches or 0.83 inches less than normal.   This ranks as the 51st warmest and 53rd driest October among 143 years of records.

Temperatures. October began with slightly cooler than normal weather for the first four days of the month.   Estherville recorded Iowa’s first freeze of the season with a 32° reading on the morning of the 2nd.   However, a lower temperature was not recorded in the state until the 14th when several northeast Iowa locations reported 30° readings.   The first hard freeze arrived at scattered northwest Iowa locations on the morning of the 16th with a 27° reading at Spencer.   The next morning brought the lowest temperatures of the month with a 19° reading at Stanley and a hard freeze over much of the northeast one-half of the state.   All of Iowa, with the exception of Des Moines and Keokuk, had recorded at least a light freeze by the end of the month.   On the other extreme, temperatures reached into the eighties somewhere in the state on the 7th, 8th, 10th, 11th, 19th, 20th and 21st.   The warmest day in most areas came on the 11th when all reporting points except Dubuque Airport and Fort Madison reached 80° with Sioux City, Hawarden and Le Mars being the hot spots with daily record 91° readings.

Heating Degree Days. Home heating requirements, as estimated by heating degree day totals, averaged 12% less than last October and 17% less than normal.   Heating degree day totals thus far this season are running 20% less than at this point last year and 23% less than normal.

Precipitation. Exceptionally dry weather prevailed from September 30 until the morning of October 20 with only a handful of locations recording any measurable rain during the period.   Parts of northwest Iowa remained dry for a few more days until rain finally moved into that portion of the state on the 23rd.   The dry, and mostly warmer than normal weather, allowed for excellent conditions for harvest and ample in-field dry-down of corn and soybeans.   Rain was more frequent late in the month with about one-half of the October total arriving on the 27th-28th.   Rain totals for the month varied from 0.54 inches at Britt to 4.07 inches on the east side of Cedar Rapids and at Iowa City.   Despite the turn to greater rainfall late in the month only a few locations, mostly in east central and far northwest Iowa, recorded above normal precipitation for the month.   Iowa’s first snow of the season arrived in the northwest on the afternoon of the 28th but with little, if any, accumulation.

The following is the number of new daily records set at COOP sites based on data back to 1951.

                 __________2015__________________________________
                 OCT  SEP  AUG  JUL  JUN  MAY  APR  MAR  FEB  JAN
Maximum High:     75  130   25   22   69   28   34  182   13  113
Minimum High:     21   13  269  261   88  316   28  102  364   65
Maximum Low:      79  336   38   54   32   82   34   29   25  135
Minimum Low:      20   25  156  139   26   87   76   98  345  111
Maximum Precip:  162  150  158  214  151  155  122   17  113   67

The following is a table summarizing how well the IEM daily data estimator is working in comparison to the quality controlled data.

                      2015
                 OCT   SEP   AUG   JUL   JUN   MAY   APR   MAR   FEB
High Temp Bias   0.2   0.0   0.1   0.0   0.0  -0.1   0.0   0.3   0.3
High Temp STD    1.8   1.7   1.8   1.7   1.7   2.5   2.2   2.6   2.8
Low  Temp Bias   0.1   0.0   0.2   0.2   0.2   0.1   0.3   0.4   0.3
Low  Temp STD    2.6   2.1   2.1   2.0   2.0   2.0   2.7   2.9   2.9
Precip    Bias  -0.01  0.01 -0.01  0.00  0.00 -0.01  0.00  0.01 -0.16
Precip    STD    0.08  0.26  0.27  0.29  0.33  0.20  0.13  0.13  0.05

1129 Views September COOP Data Uploaded

Link: https://mesonet.agron.iastate.edu/climodat/

The quality controlled Iowa COOP data for September 2015 has been uploaded to the IEM. These observations are kindly provided by Harry Hillaker, our state climatologist, who passes along these notes on the month:

General Summary. Temperatures averaged 68.4° or 5.2° above normal while precipitation totaled 4.13 inches or 0.75 inches above normal.   This ranks as the 7th warmest and 47th wettest September among 143 years of state records.   A warmer September has been recorded only once since 1939 (1998 at 68.6°).

Temperatures. Above normal temperatures were the rule for most of the month as only seven days (11th-13th, 18th-20th and 30th) averaged cooler than usual.   The heat was characterized more by persistence than extremes as no daily record high temperatures were set.   The first seven days of the month were the warmest week of the year with temperatures averaging 10.6° above normal.   Afternoon high temperatures reached into the mid-nineties in some areas each day from the 3rd through the 6th.   Highest readings were 96° temperatures at Burlington 2 S, Glenwood, Muscatine and Sidney on the 6th.   On the other extreme, Cresco and Estherville recorded 33° minimums on the morning of the 30th.

Cooling Degree Days. Home air conditioning requirements, as estimated by cooling degree day totals, averaged 184% greater than last September and 115% greater than normal.    Cooling degree day totals for the year-to-date are running 15% greater than last year at this time and 3% less than normal.

Precipitation. Rain amounts were highly variable across Iowa with totals varying from 11.63 inches at Glenwood to only 0.83 inches near Badger (Webster County).   Glenwood’s total was second only to a 12.64 inch total in 1965 among 119 years of September records at that location.   Monthly rain totals were well above normal over most of the southwest one-half of Iowa while small areas of far southeast and far northeast Iowa, as well as the Fort Dodge area, saw less than one-third of normal rainfall.   Torrential rains fell over extreme western Iowa, centered upon the morning of the 23rd, with storm totals of 9.28 inches on the north edge of Council Bluffs and 6.80 inches at Glenwood.   Excessive rains also fell on the night of the 6th over northern Guthrie/southern Greene counties, as well as Taylor and Appanoose counties, with Bagley reporting the largest total during this event with 6.25 inches.

The following is the number of new daily records set at COOP sites based on data back to 1951.

                 __________2015______________________________2014
                 SEP  AUG  JUL  JUN  MAY  APR  MAR  FEB  JAN  DEC
Maximum High:    130   25   22   69   28   34  182   13  113   84
Minimum High:     13  269  261   88  316   28  102  364   65   60
Maximum Low:     336   38   54   32   82   34   29   25  135  451
Minimum Low:      25  156  139   26   87   76   98  345  111   28
Maximum Precip:  150  158  214  151  155  122   17  113   67  121

The following is a table summarizing how well the IEM daily data estimator is working in comparison to the quality controlled data.

                      2015
                 SEP   AUG   JUL   JUN   MAY   APR   MAR   FEB   JAN
High Temp Bias   0.0   0.1   0.0   0.0  -0.1   0.0   0.3   0.3   0.2
High Temp STD    1.7   1.8   1.7   1.7   2.5   2.2   2.6   2.8   2.5
Low  Temp Bias   0.0   0.2   0.2   0.2   0.1   0.3   0.4   0.3   0.1
Low  Temp STD    2.1   2.1   2.0   2.0   2.0   2.7   2.9   2.9   2.6
Precip    Bias   0.01 -0.01  0.00  0.00 -0.01  0.00  0.01 -0.16  0.01
Precip    STD    0.26  0.27  0.29  0.33  0.20  0.13  0.13  0.05  0.04

1338 Views August COOP Data Uploaded

Link: https://mesonet.agron.iastate.edu/climodat/

The quality controlled Iowa COOP data for August 2015 has been uploaded to the IEM. These observations are kindly provided by Harry Hillaker, our state climatologist, who passes along these notes on the month:

General Summary. August temperatures averaged 69.2° or 2.3° below normal while precipitation totaled 5.41 inches or 1.21 inches above normal. This ranks as the 27th coolest and 21st wettest August among 143 years of records.

Temperatures. Summer heat was infrequent during August with daily low temperatures in the forties occurring on more days during the month (nine) than daytime highs in the nineties (seven days). Donnellson reported the month's highest temperature with a 94° reading on the 2nd while Sheldon and Spencer recorded the lowest temperatures with 40° readings on the morning of the 25th. Below normal temperatures prevailed for 13 consecutive days from the 18th through the 30th with five days during this period bringing daytime highs that were only in the sixties. "Highs" of only 61° occurred at Anamosa and Northwood on the 19th and also at New Hampton and Osage on the 28th.

Cooling Degree Days. Home air conditioning requirements, as estimated by cooling degree day totals, averaged 21% less than last August and 24% less than normal. Cooling degree day totals so far this season are running 2% less than last year at this time and 16% less than normal.

Precipitation. Mostly dry weather prevailed for the first one-half of the month with a statewide average of 1.30 inches of rain (normal for the period of 2.22 inches). However, locally heavy rains of four inches or more occurred on the night of the 8th in parts of central Iowa and the southwest corner of the state where Sidney received 5.75 inches. Much heavier rains fell during the second one-half of the month with a statewide average of 4.10 inches, or more than double the normal for the period of 1.98 inches. The bulk of the rain during this late month period arrived on the 17th-18th and 27th-28th. The first of these two events brought torrential rain to a wide area of northwest Iowa with 8.33 inches falling at Cherokee. Heaviest rains with the second event fell across central Iowa with the largest official total of 6.59 inches at Steamboat Rock while unofficial totals of nearly ten inches were reported over parts of southeast Webster County and southern Hamilton County. However, the month's heavy rain events were largely confined to central Iowa and the western one-third of the state. Most of eastern Iowa saw below normal rainfall for the month. August rain totals varied from only 1.14 inches at Keosauqua to 13.02 inches at Randolph.

Summer Summary. Temperatures during the three summer months averaged 70.3° or 1.3° below normal while precipitation totaled 17.62 inches or 3.91 inches above normal. This ranks as the 29th coolest and 7th wettest summer among 143 years of records. However, a cooler and wetter summer was recorded just last year when Iowa recorded its fifth coolest July and third wettest June.

The following is the number of new daily records set at COOP sites based on data back to 1951.

                 __________2015__________________________2014____
                 AUG  JUL  JUN  MAY  APR  MAR  FEB  JAN  DEC  NOV
Maximum High:     25   22   69   28   34  182   13  113   84   24
Minimum High:    269  261   88  316   28  102  364   65   60  634
Maximum Low:      38   54   32   82   34   29   25  135  451    5
Minimum Low:     156  139   26   87   76   98  345  111   28  550
Maximum Precip:  158  214  151  155  122   17  113   67  121   67

The following is a table summarizing how well the IEM daily data estimator is working in comparison to the quality controlled data.

                      2015
                 AUG   JUL   JUN   MAY   APR   MAR   FEB   JAN
High Temp Bias   0.1   0.0   0.0  -0.1   0.0   0.3   0.3   0.2
High Temp STD    1.8   1.7   1.7   2.5   2.2   2.6   2.8   2.5
Low  Temp Bias   0.2   0.2   0.2   0.1   0.3   0.4   0.3   0.1
Low  Temp STD    2.1   2.0   2.0   2.0   2.7   2.9   2.9   2.6
Precip    Bias  -0.01  0.00  0.00 -0.01  0.00  0.01 -0.16  0.01
Precip    STD    0.27  0.29  0.33  0.20  0.13  0.13  0.05  0.04

1367 Views July COOP Data Uploaded

Link: https://mesonet.agron.iastate.edu/climodat/

The quality controlled Iowa COOP data for July 2015 has been uploaded to the IEM. These observations are kindly provided by Harry Hillaker, our state climatologist, who passes along these notes on the month:

General Summary. Temperatures averaged 72.2° or 1.4° below normal while precipitation totaled 5.78 inches or 1.28 inches above normal.   This ranks as the 27th coolest and 19th wettest July among 143 years of records.

Temperatures. Unseasonably cool weather prevailed early in the month with nine of the first ten days of July averaging cooler than usual.   Temperatures failed to exceed 90° anywhere in the state during those opening ten days of the month with afternoon highs reaching only 61° at Donnellson, Fort Madison, Keokuk and Burlington on the 8th.   The month’s lowest temperatures were recorded during this period with 44° readings at Cresco and Elkader on the 2nd and also at Spencer on the 3rd.   However, seven of the next eight days were warmer than normal.   Temperatures reached 97° at Des Moines on the 13th and at Bellevue, Lamoni and Osceola on the 17th.   Meanwhile the heat index (what the air ‘feels like’ when humidity is considered) reached 110° at Sioux City on the 12th, 111° at Burlington on the 13th and 110° at Burlington on the 17th.   The last one-third of the month was nearly evenly divided between above and below normal temperatures.   Hawarden recorded the highest temperature with 97° on the 24th while Burlington registered the highest heat index with 109° on the 28th.   Spencer Airport was the late-month cool spot with a low of 50° on the 21st.

Cooling Degree Days. Home air conditioning requirements, as estimated by cooling degree day totals, averaged 63% greater than last July (the fifth coolest July on record) but 12% less than normal.   Cooling degree day totals thus far in 2015 are running 9% greater than last year at this time, but 12% less than normal.

Precipitation. The first two weeks of July were relatively dry, bringing a statewide average of 1.61 inches of rain (normal = 2.28) while the remainder of the month brought an average of 4.17 inches of precipitation  (normal = 2.22).   The most noteworthy early month rain event brought 3 to 5 inches of rain to much of Muscatine and Scott counties on the night of the 6th.   Rains of 3 to 5 inches fell across much of Page and Taylor Counties on the night of the 15th.   However, the most concentrated period of rain came from the 24th to the 28th.   North central Iowa was the initial focus for heavy rains with Mason City Airport picking up 4.13 inches on the 24th.   The month’s heaviest rains fell across south central Iowa on the night of the 28th with Spring Hill (Warren County) picking up 6.32 inches.   Monthly rain totals were quite variable with much of northern Iowa recording below normal July rain totals while the southern one-third of the state (with the exception of Pottawattamie County) was very wet.   Rain totals varied from 1.20 inches at the Dubuque Airport to 13.33 inches at Knoxville.   Knoxville’s total was just shy of their July record of 13.58 inches set in 1958.

The following is the number of new daily records set at COOP sites based on data back to 1951.

                 __________2015__________________________2014____
                 JUL  JUN  MAY  APR  MAR  FEB  JAN  DEC  NOV  OCT
Maximum High:     22   69   28   34  182   13  113   84   24   97
Minimum High:    261   88  316   28  102  364   65   60  634   89
Maximum Low:      54   32   82   34   29   25  135  451    5   56
Minimum Low:     139   26   87   76   98  345  111   28  550   22
Maximum Precip:  214  151  155  122   17  113   67  121   67  149

The following is a table summarizing how well the IEM daily data estimator is working in comparison to the quality controlled data.

                 2015
                 JUL   JUN   MAY   APR   MAR   FEB   JAN
High Temp Bias   0.0   0.0  -0.1   0.0   0.3   0.3   0.2
High Temp STD    1.7   1.7   2.5   2.2   2.6   2.8   2.5
Low  Temp Bias   0.2   0.2   0.1   0.3   0.4   0.3   0.1
Low  Temp STD    2.0   2.0   2.0   2.7   2.9   2.9   2.6
Precip    Bias   0.00  0.00 -0.01  0.00  0.01 -0.16  0.01
Precip    STD    0.29  0.33  0.20  0.13  0.13  0.05  0.04

1668 Views June COOP Data Uploaded

Link: https://mesonet.agron.iastate.edu/climodat/

The quality controlled Iowa COOP data for June 2015 has been uploaded to the IEM. These observations are kindly provided by Harry Hillaker, our state climatologist, who passes along these notes on the month:

General Summary. Temperatures averaged 69.6° or 0.1° below normal while precipitation totaled 6.43 inches or 1.41 inches above normal.   This ranks as the 72nd warmest and 22nd wettest June among 143 years of records.

Temperatures. Unseasonably cool weather prevailed for the first two days of June with Elkader reporting a morning low of 36° on the 1st.   However, the warmest weather of the month soon followed with above normal readings from the 3rd through the 10th.   The 9th and 10th were the hottest days with a high of 99° at Sioux City on the 9th with 97° maximums at Clarinda, Shenandoah and Sidney on the 10th.   The last three weeks of the month were mostly on the cool side of normal but with daily averages never more than five degrees away from normal.   Temperature extremes for the second one-half of the month varied from a high of 97° at Lamoni on the 20th to a low of 48° at Sanborn on the 16th.

Cooling Degree Days. Home air conditioning requirements, as estimated by cooling degree day totals, averaged 7% less than normal and 11% less than last June.   Cooling degree day totals thus far this air conditioning season are running 12% less than normal and 22% less than at this time last year.

Precipitation. A relatively dry period prevailed for the first seven days of June, however rain was frequent for the remainder of the month.   Greatest rains fell from the 10th to the 12th and 20th through the 25th.   Rains with the first wet period were especially heavy in far southwest Iowa and in the Cedar Rapids area where amounts of 4 to 6 inches were common.   The most intense rains of the month fell on the night of the 24th across central Iowa from Greene County southeast to Monroe County.   Columbia in Marion County recorded the most rain with 7.30 inches.   The Raccoon River (at Fleur Drive) and the Des Moines River (at SE 6th St.) in Des Moines both recorded their third highest crests of record on June 26 (behind 1993 and 2008).   However, monthly rain totals were below normal over parts of northern Iowa, particularly in the northwest where amounts were only about one-half of normal in Sioux, O’Brien, Clay, Dickinson and Emmet counties.   June rain totals varied from 2.07 inches at Everly to 13.54 inches at Waukee.   This was the second wettest June on record at Bloomfield, Donnellson, Guthrie Center and Vinton.

Severe Weather. Severe weather was more frequent than in previous months this year with hail or high winds reported somewhere in the state on 13 days during the month.   The most widespread severe weather occurred on the 20th, 22nd and 24th.   The most noteworthy outbreak was on 22nd when a derecho brought widespread damaging winds to much of the northern one-third of the state during the morning while storms redeveloped in the late afternoon across southeast Iowa with an EF-3 tornado occurring in Monroe County.

The following is the number of new daily records set at COOP sites based on data back to 1951.

                 _____2015__________________________2014_________
                 JUN  MAY  APR  MAR  FEB  JAN  DEC  NOV  OCT  SEP
Maximum High:     69   28   34  182   13  113   84   24   97   25
Minimum High:     88  316   28  102  364   65   60  634   89  267
Maximum Low:      32   82   34   29   25  135  451    5   56   86
Minimum Low:      26   87   76   98  345  111   28  550   22  180
Maximum Precip:  151  155  122   17  113   67  121   67  149  176

The following is a table summarizing how well the IEM daily data estimator is working in comparison to the quality controlled data.

                 2015
                 JUN   MAY   APR   MAR   FEB   JAN
High Temp Bias   0.0  -0.1   0.0   0.3   0.3   0.2
High Temp STD    1.7   2.5   2.2   2.6   2.8   2.5
Low  Temp Bias   0.2   0.1   0.3   0.4   0.3   0.1
Low  Temp STD    2.0   2.0   2.7   2.9   2.9   2.6
Precip    Bias   0.00 -0.01  0.00  0.01 -0.16  0.01
Precip    STD    0.33  0.20  0.13  0.13  0.05  0.04

1674 Views May COOP Data Uploaded

Link: https://mesonet.agron.iastate.edu/climodat/

The quality controlled Iowa COOP data for May 2015 has been uploaded to the IEM. These observations are kindly provided by Harry Hillaker, our state climatologist, who passes along these notes on the month:

General Summary. Temperatures averaged 60.0° or 0.1° below normal while precipitation totaled 5.08 inches or 0.52 inches above normal.   This ranks as the 69th warmest and 35th wettest May among 143 years of records.

Temperatures. There were two extended periods of warmer than normal weather from the 2nd through the 10th and from the 23rd through the 29th.   Nevertheless, relatively brief but intense cold spells, particularly from the 18th through the 22nd, were just enough to pull the statewide average temperature barely below normal for the month as a whole.   Temperature extremes varied from a high of 89° at Little Sioux on the 3rd to lows of 31° on the 1st at Elkader and Lowden.   There were no freezes recorded after the 1st although Belle Plaine came close with a 33° reading on the 21st.   This was the first May since 1995 when temperatures failed to reach 90°, as well as the smallest range in May temperature extremes since that year.

Heating Degree Days. Home heating requirements, as estimated by heating degree day accumulations, averaged 6% less than normal and 14% less than last May.   Heating degree day totals for the 2014-2015 heating season (since July 1, 2014) are running 1% greater than normal but 11% less than during the long cold season of one year ago.

Precipitation. Rainfall was very frequent during May.   Measurable rainfall (0.01 inch or more) fell on an average of 17 days at any single location in the state, 45% more frequently than typical in May (which averages the most rain days of any month of the year).   Red Oak recorded 22 days with measurable rain and another three days with trace amounts.   Monthly rain totals varied from 2.68 inches at Newton to 9.21 inches at a gage five miles east of Denison.   Greatest totals were generally over southwestern Iowa while below normal totals were mostly in a wide band from near Ottumwa northward to Mason City.   The wettest period of this wet month came between the evening of the 23rd and morning of the 27th when a statewide average of 1.56 inches of rain fell.   Despite the frequent May rainfall, year-to-date precipitation totals are below normal over most of the state with greatest deficits over the northwest and southeast corners of Iowa.   Year-to-date precipitation surpluses are mostly confined to southwest and west central Iowa, roughly the same areas that were unusually wet in 2014.

Spring Summary. Temperatures over the three spring months of March, April and May averaged 49.2° or 0.9° above normal while precipitation totaled 9.05 inches or 1.17 inches below normal.   This ranks as the 46th warmest and 70th wettest spring among 143 years of records.   A drier year-to-date was last recorded in 2003, although this year is just a few hundredths of an inch drier than last year at this time.   The relative warmth of this spring, an extended period of mostly dry weather in late April, and the lack of widespread heavy rain events have allowed most of the state (the southwest being the primary exception) to experience good planting progress despite the high frequency of rain over the past month.

The following is the number of new daily records set at COOP sites based on data back to 1951.

                 2015__________________________2014______________
                 MAY  APR  MAR  FEB  JAN  DEC  NOV  OCT  SEP  AUG
Maximum High:     28   34  182   13  113   84   24   97   25   25
Minimum High:    316   28  102  364   65   60  634   89  267  161
Maximum Low:      82   34   29   25  135  451    5   56   86  113
Minimum Low:      87   76   98  345  111   28  550   22  180   33
Maximum Precip:  155  122   17  113   67  121   67  149  176  182

The following is a table summarizing how well the IEM daily data estimator is working in comparison to the quality controlled data.

                 2015
                 MAY   APR   MAR   FEB   JAN
High Temp Bias  -0.1   0.0   0.3   0.3   0.2
High Temp STD    2.5   2.2   2.6   2.8   2.5
Low  Temp Bias   0.1   0.3   0.4   0.3   0.1
Low  Temp STD    2.0   2.7   2.9   2.9   2.6
Precip    Bias  -0.01  0.00  0.01 -0.16  0.01
Precip    STD    0.20  0.13  0.13  0.05  0.04

1416 Views April COOP Data Uploaded

Link: https://mesonet.agron.iastate.edu/climodat/

The quality controlled Iowa COOP data for April 2015 has been uploaded to the IEM. These observations are kindly provided by Harry Hillaker, our state climatologist, who passes along these notes on the month:

General Summary. Iowa temperatures averaged 50.7° or 1.8° above normal while precipitation totaled 3.37 inches of 0.14 inches below normal.   This ranks as the 40th warmest and 49th wettest April among 143 years of records.   This was the driest April since 2004.

Temperatures. The warmest day of the month was the first day when temperatures climbed into the eighties over most of Iowa and reached a maximum of 88° at Little Sioux.   Only a few locations in extreme western Iowa and far southeast Iowa reached the 80 degree mark during the remainder of the month.   The month’s lowest temperatures were 19° readings at Elkader and Belle Plaine on the morning of the 4th.   Also noteworthy was a late month cold snap that brought a hard freeze to many areas on the 22nd and 23rd with lowest readings of 22° at Cresco, Decorah, Elkader and Mason City on the 23rd.

Heating Degree Day Totals. Home heating requirements, as estimated by heating degree day totals, averaged 21% less than last April and 14% less than normal.   Thus far this heating season (since July 1, 2014) degree day totals have averaged 11% less than the harsh winter of one year ago, but 2% greater than normal.

Precipitation. Rainfall amounts varied greatly during the month with relatively wet conditions prevailing from west central to north central Iowa.   Driest conditions, with some areas seeing less than one-third of normal April amounts, were across the southeast and extreme northwest corners of the state.   Totals varied from 1.18 inches at Rock Valley to 6.88 inches at Lake Mills where localized heavy thunderstorms dumped 4.44 inches of rain between the 7th and 9th.   Moderate drought conditions have edged into far northwest Iowa in response to a dry weather pattern prevailing in that area of the state (and extending over much of Minnesota and the Dakotas) since last summer.   Snow occurred only twice during the month.   Rain turned to snow from west central to north central Iowa on the afternoon and evening of the 9th with a maximum of four inches reported at Schleswig in Crawford County.   Some snow was also reported across parts of northeast Iowa on the 21st but with no accumulation.   The statewide average snowfall was just 0.2 inches for the month while normal is 1.6 inches.   This brings the seasonal snow total to 26.8 inches or 5.4 inches below normal.   This has been only the second season in the past nine to bring a below normal total in Iowa.   This ranks as the 47th lowest seasonal total among 128 years of records.

Severe Weather. The year’s first two tornadoes were reported over east central Iowa on the evening of April 9.   Overall severe storms were infrequent during the month with a few large hail reports on the 7th, 8th, 9th, 18th and 19th with all of the reports coming from southern and eastern Iowa.

The following is the number of new daily records set at COOP sites based on data back to 1951.

                 2015_____________________2014___________________
                 APR  MAR  FEB  JAN  DEC  NOV  OCT  SEP  AUG  JUL
Maximum High:     34  182   13  113   84   24   97   25   25    4
Minimum High:     28  102  364   65   60  634   89  267  161  399
Maximum Low:      34   29   25  135  451    5   56   86  113    8
Minimum Low:      76   98  345  111   28  550   22  180   33  330
Maximum Precip:  122   17  113   67  121   67  149  176  182  134

The following is a table summarizing how well the IEM daily data estimator is working in comparison to the quality controlled data.

                 2015
                 APR   MAR   FEB   JAN
High Temp Bias   0.0   0.3   0.3   0.2
High Temp STD    2.2   2.6   2.8   2.5
Low  Temp Bias   0.3   0.4   0.3   0.1
Low  Temp STD    2.7   2.9   2.9   2.6
Precip    Bias   0.00  0.01 -0.16  0.01
Precip    STD    0.13  0.13  0.05  0.04

1278 Views March COOP Data Uploaded

Link: https://mesonet.agron.iastate.edu/climodat/

The quality controlled Iowa COOP data for March 2015 has been uploaded to the IEM. These observations are kindly provided by Harry Hillaker, our state climatologist, who passes along these notes on the month:

General Summary. Iowa temperatures averaged 36.9° or 1.0° above normal while precipitation totaled 0.60 inches or 1.55 inches below normal.   This ranks as the 53rd warmest and ties for 7th driest March among 143 years of records.   A drier March was last recorded in 1994 and a drier first one-quarter year in 1988.

Temperatures. The very cold weather pattern that dominated most of February continued into the first six days of March.   The coldest day in many areas was the 5th with morning lows down to -17° at Stanley in Buchanan County while Maquoketa, Oelwein, Stanley and Postville recorded daytime highs of only 9°.   An extended period of warmer and drier than normal weather prevailed from the 7th through the 22nd.  The year’s first 70 degree readings were recorded over much of southwestern Iowa on the 10th while Little Sioux reached 81° on the 15th.   Temperature soared higher still with Sioux City reaching 90° on the 16th.   This reading came six days earlier in the year than any previous 90° temperature in Iowa (old record 92° at Clarinda on March 22, 1910).   Another spell of cold weather prevailed from the 23rd to the 28th with Cresco reporting a low of 8° on the morning of the 27th.   Finally, mild weather returned for the end of the month with Little Sioux reaching 81° on the 30th  and 80° on the 31st..   A larger range in monthly temperature extremes from -17 to +90 has been recorded only three times during March (1943, 1959 and 1962).   There was also a fairly strong gradient in temperatures across Iowa during March with the month averaging about 5 degrees warmer than normal over the far northwest to about 2 degrees below normal along the Mississippi River.

Heating Degree Day Totals. Home heating requirements, as estimated by heating degree day totals, averaged 4% less than normal and 21% less than last March.   Degree day totals for the heating season (since July 1, 2014) are running 3% more than normal but 10% less than last season though the end of March.

Precipitation. Most of Iowa has been unusually dry since the major snow storm of January 31-February 1.   There has been a statewide average of only 0.89 inches from February 2 through the end of March compared to a normal total for the period of 3.14 inches.   A particularly dry period occurred from March 4th through the 21st when a statewide average of only 0.01 inches of precipitation fell during this 18-day period.   Most of March’s precipitation came in two events during the fourth week of the month.   Heavy snow fell across far northeast Iowa on the night of the 22nd with a foot of wet snow reported at McGregor.   The largest event came on the 24th when rain fell statewide.   Rain totals exceeded an inch at a few western locations with a maximum total of 1.32 inches reported near New Market in Taylor County.   Some of the precipitation fell in the form of freezing rain and snow over northern sections of the state.   This event also brought the first thunderstorms of the year to portions of the state.   Monthly precipitation totals varied from 0.03 inches at Guthrie Center to 1.77 inches at Monona.   No measurable snow fell over much of western and central Iowa during the month while 12.5 inches was reported eight miles east-northeast of Decorah.   The statewide average snowfall was 0.9 inches while normal for the month is 4.7 inches.   This was the lowest March statewide average snowfall since 1994 and ranks 9th lowest among 128 years of records.

The following is the number of new daily records set at COOP sites based on data back to 1951.

                 2015________________2014________________________
                 MAR  FEB  JAN  DEC  NOV  OCT  SEP  AUG  JUL  JUN
Maximum High:    182   13  113   84   24   97   25   25    4   27
Minimum High:    102  364   65   60  634   89  267  161  399   37
Maximum Low:      29   25  135  451    5   56   86  113    8  122
Minimum Low:      98  345  111   28  550   22  180   33  330   58
Maximum Precip:   17  113   67  121   67  149  176  182  134  342

The following is a table summarizing how well the IEM daily data estimator is working in comparison to the quality controlled data.

                 2015
                 MAR   FEB   JAN
High Temp Bias   0.3   0.3   0.2
High Temp STD    2.6   2.8   2.5
Low  Temp Bias   0.4   0.3   0.1
Low  Temp STD    2.9   2.9   2.6
Precip    Bias   0.01 -0.16  0.01
Precip    STD    0.13  0.05  0.04

1129 Views February COOP Data Uploaded

Link: https://mesonet.agron.iastate.edu/climodat/

The quality controlled Iowa COOP data for February 2015 has been uploaded to the IEM. These observations are kindly provided by Harry Hillaker, our state climatologist, who passes along these notes on the month:

General Summary. Iowa temperatures averaged 14.0° or 10.0° below normal while precipitation totaled 1.17 inches or 0.12 inches above normal.   This ranks as the 10th coldest and 60th wettest February among 143 years of records.

Temperatures. Cold weather was the rule for most of the month as temperatures averaged above normal only for the five days from the 6th through the 10th.   The second one-half of the month was particularly cold as 7 of the final 11 days of February averaged more than twenty degrees below normal.   The first very cold air mass of the month settled in on the morning of the 5th when temperatures fell to -25° at Elkader with valley bottom temperatures falling to -23° as far south as Centerville.   The winter’s lowest temperatures occurred on the last two days of the month with Stanley recording -30° on the morning of the 27th with Elkader matching that  reading the next morning.   Elkader’s reading was the nationwide low (lower 48 states) on the 28th.    A lower temperature has been recorded later in the winter season in Iowa only three times (1948, 1960 and 1962).   Overall, temperatures fell to zero or lower on 18 days during the month.   Wind chill readings fell into the minus 30s on five days during the month with Clarion reporting the lowest wind chill at -38° on the morning of the 27th.   On the other extreme temperatures climbed to 51° at Keokuk on the 7th, Glenwood and Shenandoah on the 8th and at Clarinda and Shenandoah on the 25th.

Heating Degree Day Totals. Home heating requirements, as estimated by heating degree day totals, averaged 3% less than last February (which was 1.5° colder than this February) but was 24% greater than normal.   Degree day totals so far this season (since July 1) are running 8% less than last season at this time, but 4% more than normal.

Precipitation. The bulk of the month’s precipitation fell as snow and came in two events.   The largest event began on January 31 and continued into the evening of February 1.   Snow fell statewide with greatest amounts falling across central and east central Iowa with amounts up to 16.0 inches at Le Claire and 14.7 inches at Madrid.   A statewide average of 8.6 inches of snow fell with this storm which is the largest snow event since December 23-27, 2009.   Another event on the 25th brought widespread 3 to 6 inch snow totals to the northeast one-half of Iowa but only a dusting over the southwest counties.   Volga (Clayton Co.) reported the most snow with this event with 7.4 inches.   Snow also fell across the southern one-third of the state on the 4th with 6.5 inches reported at Shenandoah.   Monthly snowfall totals varied from 3.2 inches near Spirit Lake to 20.2 inches at Le Claire.   The statewide average snowfall was 12.8 inches or 6.0 inches above normal.   This ranks as the 10th snowiest February among 128 years of records.

Winter Summary. Temperatures over the mid-winter months of December, January and February averaged 21.1° or 1.0° below normal while precipitation totaled 2.87 inches or 0.47 inches less than normal.   This ranks as the 60th coolest and 55th driest winter among 142 years of records.

The following is the number of new daily records set at COOP sites based on data back to 1951.

                 2015___________2014_____________________________
                 FEB  JAN  DEC  NOV  OCT  SEP  AUG  JUL  JUN  MAY
Maximum High:     13  113   84   24   97   25   25    4   27   79
Minimum High:    364   65   60  634   89  267  161  399   37  235
Maximum Low:      25  135  451    5   56   86  113    8  122  102
Minimum Low:     345  111   28  550   22  180   33  330   58  171
Maximum Precip:  113   67  121   67  149  176  182  134  342   92

The following is a table summarizing how well the IEM daily data estimator is working in comparison to the quality controlled data.

                 2015
                 FEB   JAN
High Temp Bias   0.3   0.2
High Temp STD    2.8   2.5
Low  Temp Bias   0.3   0.1
Low  Temp STD    2.9   2.6
Precip    Bias  -0.16  0.01
Precip    STD    0.05  0.04

1110 Views January COOP Data Uploaded

Link: http://mesonet.agron.iastate.edu/climodat/

The quality controlled Iowa COOP data for January 2015 has been uploaded to the IEM. These observations are kindly provided by Harry Hillaker, our state climatologist, who passes along these notes on the month:

General Summary. Iowa temperatures averaged 21.3° or 1.9° above normal while precipitation totaled 0.56 inches or 0.36 inches below normal.   This ranks as the 51st warmest and 33rd driest January among 143 years of records.

Temperatures. The month had a split personality for temperatures with most of the first two weeks of January averaging below normal while the month finished with 17 consecutive warmer than normal days.   Wind chill readings dipped below -30° on the 4th, 6th, 7th and 8th with lowest readings of -35° at Clarion, Spencer and Storm Lake on the morning of the 6th and again at Clarion and Mason City on the morning of the 7th.   Actual temperatures bottomed out at -25° at Cherokee on the morning of the 13th.   Temperatures dipped below zero somewhere in the state every day from the 4th through the 14th.   However, the lowest temperature for the remainder of the month was 6° above zero at Cresco on the 30th.   Daytime highs reached into the sixties on the 16th (62° at Clarinda, Red Oak and Shenandoah) and 28th (67° at Shenandoah) over southwestern Iowa.   The Shenandoah reading on the 28th was a record high for that date and location (old record 61° in 2013).

Heating Degree Day Totals. Home heating requirements, as estimated by heating degree day totals, averaged 15% less than last January and 5% less than normal.   Heating degree day totals so far this heating season are running 9% less than last year at this time and1% less than normal.

Precipitation. The relatively dry weather pattern that has prevailed in Iowa since mid-October persisted until January 31st when Iowa’s heaviest snow storm in five years arrived.   This late month storm began with rain on the morning of the 31st with the rain gradually changing to snow during the afternoon and evening hours.   Snow fell statewide before ending during the afternoon and evening of February 1st.   Storm totals varied from 2.2 inches near Spirit Lake to 16.0 inches at Le Claire.   Greatest amounts fell along and just north of the Interstate 80 corridor from Des Moines to the Quad Cities.   A statewide average of 8.5 inches of snow fell across Iowa, the highest storm total since December 23-27, 2009.   However, the vast majority of Iowa’s weather stations make their once-daily observations at 7 a.m., prior to the arrival of the storm on the 31st.   Thus, most of the precipitation and snowfall from this storm will go into the record books for February.   The month’s greatest precipitation total was 1.64 inches at Burlington with Lowden reporting the most snow with 15.1 inches (both of these locations measure at midnight).   However, for the month ending at 7 a.m. January 31, only 0.02 inches of precipitation fell at Hastings while New Market recorded only 0.4 inches of snow for the same period.    The largest precipitation event occurring entirely within January came on the 5th with widespread snowfall of four to six inches from northwest to east central Iowa.   High winds combined with dry powdery snow to result in blizzard warnings being issued for parts of northern Iowa on the night of the 3rd and again on the 8th.   The statewide average snowfall for the month was 6.3 inches.   This is 1.4 inches below normal and ranks as the 53rd lowest January total among 128 years of record.

The following is the number of new daily records set at COOP sites based on data back to 1951.

                 2015___________2014_____________________________
                 JAN  DEC  NOV  OCT  SEP  AUG  JUL  JUN  MAY  APR
Maximum High:    113   84   24   97   25   25    4   27   79  118
Minimum High:     65   60  634   89  267  161  399   37  235  174
Maximum Low:     135  451    5   56   86  113    8  122  102   40
Minimum Low:     111   28  550   22  180   33  330   58  171  209
Maximum Precip:   67  121   67  149  176  182  134  342   92  187

The code that generates the monthly estimated data got a major overhaul in August with the estimates for January regenerated. I am also computing these statistics differently going forward, so we'll start the table fresh this month.

                 2015
                 JAN
High Temp Bias   0.2
High Temp STD    2.5
Low  Temp Bias   0.1
Low  Temp STD    2.6
Precip    Bias   0.01
Precip    STD    0.04

1341 Views December COOP Data Uploaded

Link: http://mesonet.agron.iastate.edu/climodat/

The quality controlled Iowa COOP data for December 2014 has been uploaded to the IEM. These observations are kindly provided by Harry Hillaker, our state climatologist, who passes along these notes on the month:

General Summary. Iowa temperatures averaged 28.1° or 5.2°above normal while precipitation totaled 1.14 inches or 0.20 inches below normal. This ranks as the 35th warmest and 67th wettest December among 142 years of records.

Temperatures. The cold weather pattern that dominated the month of November persisted only into the first three days of December. Above normal temperatures prevailed on all but two days between the 4th and 28th. There were two prolonged periods averaging more than ten degrees warmer than normal from the 12th through the 15th and from the 21st through the 26th when overnight low temperatures were frequently higher than typical daytime high readings. The month's highest temperatures of 60° were recorded on the 14th at Shenandoah and Sidney. Subzero temperatures were confined to only December 1st, and again over the last four days of the month. Sanborn recorded the lowest temperature of the month with a -16° reading on the morning of the 30th while wind chills bottomed out at -33° the same morning at Storm Lake. Soils, which had frozen to a depth of three to eight inches during the unusually cold November, were completed thawed in many areas by Christmas. However, frost depths quickly returned to the 3 to 8 inch range in response to sharply colder weather at the end of December.

Heating Degree Day Totals. Home heating requirements averaged 23% less than last December and 13% less than normal for the month. Heating requirements thus far this winter season (since July 1) are running 6% less than last year at this time but are 1% more than normal.

Precipitation. December began very dry with no measurable precipitation anywhere in the state until the 7th. Most of the month's precipitation came in two events. The first storm system brought light to moderate rain statewide from the 14th to the 16th with the rain changing to very light snow in the far northwest late in the event. The second event also brought light to moderate rain statewide between the 22nd and 24th before changing over to one to four inches of snow across the northwest one-half of the state. One last event brought one to four inches of snow to the northwest one-third of Iowa on the night of the 26th. Monthly precipitation totals, coming mostly as rain, were above normal over most of northwestern Iowa but decreased to about one-half of normal over the far southeast. Precipitation totals varied from 0.47 at Allerton to 2.51 inches at Little Sioux. The statewide average snowfall for the month was only 1.6 inches or 6.7 inches below normal. This is the lowest December snow total since 2006 and 13th lowest among 128 years of records. Numerous locations in eastern Iowa had no measurable snow during the month such as Davenport, Dubuque and Iowa City. Saint Ansgar reported the most snow with 8.1 inches.

Annual Summary. Iowa's 2014 temperatures averaged 45.4° or 2.7° below normal while precipitation totaled 39.66 inches or 4.39 inches above normal. This ranks as the 6th coolest and 14th wettest year among 142 years of records. A cooler year was last recorded in 1917 and a wetter one in 2010. Annual temperature extremes varied from a low of -29° at Elkader on January 28 and February 11 and a high of 98° at Sidney on July 25. There were three months ranking among the top ten for low temperatures (February 7th coldest among Februarys, July 5th coolest and November 4th coldest; while only December averaged more than one degree above normal. Annual precipitation totals varied from 25.93 inches at Estherville to 56.35 inches at Greenfield. Record high annual precipitation totals were recorded at Greenfield, Castana, Denison and Mapleton.

The following is the number of new daily records set at COOP sites based on data back to 1951.

                 __________2014__________________________________
                 DEC  NOV  OCT  SEP  AUG  JUL  JUN  MAY  APR  MAR
Maximum High:     84   24   97   25   25    4   27   79  118   24
Minimum High:     60  634   89  267  161  399   37  235  174  406
Maximum Low:     451    5   56   86  113    8  122  102   40    7
Minimum Low:      28  550   22  180   33  330   58  171  209  439
Maximum Precip:  121   67  149  176  182  134  342   92  187   29

The following is some bulk statistics on how well IEM's daily COOP data estimator is performing on a monthly basis versus this QC'd dataset.

                 ___________2014_______________________________
                 DEC   NOV   OCT   SEP   AUG   JUL   JUN   MAY
High Temp Bias  -0.5   0.4   0.4   0.2   0.0   0.2   0.1   0.2
High Temp RMSE   0.9   0.8   0.8   0.8   0.7   0.8   0.7   0.8
Low  Temp Bias  -0.9   0.1   0.2   0.2   0.1   0.2   0.1   0.1
Low  Temp RMSE   1.0   0.9   0.9   0.9   0.8   1.0   0.8   0.9
Precip    Bias   0.03  0.15  0.26  0.33  0.39  0.2   0.13  0.20
Precip    RMSE   0.20  0.25  0.51  0.75  1.11  0.92  1.39  0.64

1900 Views November COOP Data Uploaded

Link: http://mesonet.agron.iastate.edu/climodat/

The quality controlled Iowa COOP data for November 2014 has been uploaded to the IEM. These observations are kindly provided by Harry Hillaker, our state climatologist, who passes along these notes on the month:

General Summary. Iowa temperatures averaged 29.1° or 7.5° below normal while precipitation averaged 0.82 inches or 1.23 inches below normal.   This ranks as the 4th coldest and 33rd driest November among 142 years of records.   A colder November was last recorded in 1991 and a drier one in 2007.

Temperatures. Unseasonably cold weather was persistent during the month with below normal temperatures prevailing for 21 days in November.   Temperatures failed to climb above freezing anywhere in the state between 9 a.m. November 11 and 1 a.m. November 19.   At Des Moines a streak of 252 consecutive hours below freezing began at midnight on the night of the 10th.   This streak was 48 hours longer than recorded in any other November among 137 years of records.   The season’s first subzero temperature was recorded at Little Sioux with a -2° reading on the morning of the 14th.   There were another six days in the month with temperatures falling to zero or below.   Swea City reported the lowest temperature with a -16° reading on the morning of the 27th.   However, despite the prevalence of unusually cold weather there were some brief, but sizable, warms spells.   Keosauqua reported the highest temperature of the month with a 72° maximum on the 10th where temperatures fell fifty degrees by the next morning.   A late month warm spell on the 29th pushed temperatures up to 66° at Glenwood, Lamoni and Castana and melted most of the state’s snow cover.

Heating Degree Day Totals. Home heating requirements, as estimated by heating degree day totals, averaged 25% greater than normal and 14% greater than last November.   Heating degree day totals so far this heating season (since July 1) are running 13% greater than normal and 10% greater than last year at this time.

Precipitation. The relatively dry weather pattern that began in mid-October continued through November.   November’s monthly precipitation totals varied from only 0.17 inches at Battle Creek (Ida County) to 2.43 inches at Brighton (Washington County).   Brighton was the only location in Iowa to report above normal precipitation during the month.   The season’s first accumulating snow arrived on the night of the 10th and brought one-half to two inches of snow to the northwest one-half of the state.   The month’s largest snow event brought snow statewide on the 15th-16th with amounts up to 5.5 inches at Ringsted (Emmet County).   The month’s largest precipitation event began with rain statewide on the 23rd and transitioned to snow across the east by late that night.   Northwest Iowa received only very light precipitation while several locations in Clinton County picked up more than 1.7 inches of rain.   Finally, snow fell over much of Iowa on the 26th with 6.0 inches reported at Emmetsburg, Britt and Rose Hill while Brighton recorded 6.8 inches.   Monthly snow totals varied from one inch at Keokuk and Shenandoah to 11.4 inches at Emmetsburg.   The statewide average snowfall was 5.0 inches or 2.3 inches above normal.   This was the snowiest November since 1991 and ranks 21st most snow among the past 128 Novembers

Fall Summary. Temperatures over the three autumn months of September, October and November averaged 47.4° or 2.8° below normal while precipitation totaled 8.39 inches or 0.36 inches above normal.   This ranks as the 12th coldest and 49th wettest fall among 142 years of records.   This was the coolest fall since 1993 although this was nearly all a result of the unseasonably cold November.   This was also the wettest fall in five years with the first half of the season much wetter than the second half.

The following is the number of new daily records set at COOP sites based on data back to 1951.

                 __________2014__________________________________
                 NOV  OCT  SEP  AUG  JUL  JUN  MAY  APR  MAR  FEB
Maximum High:     24   97   25   25    4   27   79  118   24   26
Minimum High:    634   89  267  161  399   37  235  174  406  306
Maximum Low:       5   56   86  113    8  122  102   40    7    7
Minimum Low:     550   22  180   33  330   58  171  209  439  379
Maximum Precip:   67  149  176  182  134  342   92  187   29   91

The following is some bulk statistics on how well IEM's daily COOP data estimator is performing on a monthly basis versus this QC'd dataset.

                 ___________2014_______________________________
                 NOV   OCT   SEP   AUG   JUL   JUN   MAY   APR
High Temp Bias   0.4   0.4   0.2   0.0   0.2   0.1   0.2   0.4
High Temp RMSE   0.8   0.8   0.8   0.7   0.8   0.7   0.8   0.8
Low  Temp Bias   0.1   0.2   0.2   0.1   0.2   0.1   0.1   0.2
Low  Temp RMSE   0.9   0.9   0.9   0.8   1.0   0.8   0.9   1.0
Precip    Bias   0.15  0.26  0.33  0.39  0.2   0.13  0.20  0.14
Precip    RMSE   0.25  0.51  0.75  1.11  0.92  1.39  0.64  0.63

2628 Views October COOP Data Uploaded

Link: http://mesonet.agron.iastate.edu/climodat/

The quality controlled Iowa COOP data for October 2014 has been uploaded to the IEM. These observations are kindly provided by Harry Hillaker, our state climatologist, who passes along these notes on the month:

General Summary. Temperatures averaged 51.1° or 0.3° above normal while precipitation totaled 3.20 inches or 0.59 inches above normal.   This ranks as the 63rd coolest and 36th wettest October among 142 years of records.

Temperatures. The statewide average temperature was above normal for only the second month this year (June was the other).   Cooler than usual weather dominated much of the first twelve days of the month but was followed by an extended period of milder weather with above normal temperatures prevailing on all but one day from the 13th through the 28th.   Temperatures reached 80° at Sioux City on the 1st and at Lowden on the 27th while the warmest weather came on the 26th when Sidney reached 85°.   There were frequent episodes of freezing weather during the month but the first widespread hard freeze came on the morning of the 11th when Elkader, Mason City and Sheldon reported morning lows of 25°.   Similar readings also occurred on the morning of the 30th while the first nearly statewide hard freeze (a handful of locations along the Mississippi River did not record a freeze during October) came on the last day of the month with morning lows down to 19° at Primghar, Rock Rapids and Sheldon.   Finally, Spencer Airport recorded the lowest temperature of the month at midnight at the end of the 31st with a reading of 17°.

Precipitation. Widespread precipitation from September 30 into October 3 brought harvest activities to a halt across most of Iowa.   Greatest rain totals from this event fell over southwest Iowa where Oakland recorded 4.40 inches while the least fell across the far northwest where Rock Rapids picked up only 0.31 inches.   A second widespread rain event from the 12th through the 14th brought rain totals varying from just a trace at Estherville and Spencer to 4.61 inches at Pella.   A very welcome period of much drier weather prevailed for the remainder of the month with the exception of some light to moderate rain on the 22nd-23rd.   Monthly precipitation totals varied from 0.75 inches at Rock Rapids to 6.41 inches at Oakland.   According to Iowa Agricultural Statistics the frequent early wet weather allowed only 9% of the soybean crop to be harvested by October 5, the lowest percentage completed by this date in over 30 years.   However, the late month dryness finally allowed the soybean harvest to progress slightly ahead of the normal pace by November 2.   Snow flurries were observed over portions of northern and eastern Iowa on the morning of the 4th.   This was the earliest recorded snow in Iowa since 1999 but proved to be the only occurrence during the month.

Heating Degree Day Totals. Home heating requirements, as estimated by heating degree day totals, averaged 7% less than last October and 5% less than normal.   Degree day totals so far this heating season (since July 1) are running 4% greater than one year ago but 4% less than normal.

The following is the number of new daily records set at COOP sites based on data back to 1951.

                 __________2014__________________________________
                 OCT  SEP  AUG  JUL  JUN  MAY  APR  MAR  FEB  JAN
Maximum High:     97   25   25    4   27   79  118   24   26   79
Minimum High:     89  267  161  399   37  235  174  406  306  219
Maximum Low:      56   86  113    8  122  102   40    7    7   22
Minimum Low:      22  180   33  330   58  171  209  439  379  194
Maximum Precip:  149  176  182  134  342   92  187   29   91   36

The following is some bulk statistics on how well IEM's daily COOP data estimator is performing on a monthly basis versus this QC'd dataset.

                 ___________2014_______________________________
                 OCT   SEP   AUG   JUL   JUN   MAY   APR   MAR
High Temp Bias   0.4   0.2   0.0   0.2   0.1   0.2   0.4   1.3
High Temp RMSE   0.8   0.8   0.7   0.8   0.7   0.8   0.8   1.8
Low  Temp Bias   0.2   0.2   0.1   0.2   0.1   0.1   0.2   2.1
Low  Temp RMSE   0.9   0.9   0.8   1.0   0.8   0.9   1.0   2.4
Precip    Bias   0.26  0.33  0.39  0.2   0.13  0.20  0.14  0.36
Precip    RMSE   0.51  0.75  1.11  0.92  1.39  0.64  0.63  0.46

2671 Views September COOP Data Uploaded

Link: http://mesonet.agron.iastate.edu/climodat/

The quality controlled Iowa COOP data for September 2014 has been uploaded to the IEM. These observations are kindly provided by Harry Hillaker, our state climatologist, who passes along these notes on the month:

General Summary. Temperatures averaged 62.1° or 1.1° below normal while precipitation totaled 4.37 inches or 0.99 inches above normal. This ranks as the 45th coolest and 40th wettest September among 142 years of records.

Temperatures. Temperatures were on the cool side of normal for 17 of the first 23 days of the month. Most noteworthy was an unseasonably cold period from the 11th through the 16th. Daytime high temperatures on the 12th were only in the forties as far south as Ringgold and Union counties. At Dubuque their calendar day high of 48° on the 12th came a full week sooner than the previous earliest sub-50° maximum in 140 years of records in that city. The next morning frost was scattered across much of the state with the lowest official readings of 31° recorded at Elkader, Estherville, Mason City, Sheldon, Sioux Center, Spencer, Stanley and Webster City. These were the lowest temperatures recorded for so early in the season in Iowa since Elkader recorded 29° on September 10, 1976. Frost was also reported in a few areas on the morning of the 16th when official temperature readings bottomed out at 33° at Battle Creek, Elkader, Sheldon and Stanley. However, a brief warm-up came on the 4th when nearly one-half of Iowa saw temperatures in the nineties with highest readings of 94° at Donnellson, Glenwood, Shenandoah and Sidney. Little Sioux and Sioux City also reached 90° on the 19th. Finally, temperatures frequently climbed into the eighties from the 25th through the 29th.

Precipitation. September began with a widespread rain event exiting the state and ended with another large rain event entering Iowa. Rain was frequent over the first twelve days of the month with the largest event coming on the night of the 9th. Rain amounts of three to five inches were widespread with this event across the southern one-third of the state with a maximum of 5.41 inches reported near Hartford in Warren County. Thanks to the frequent early month rains the September 16 edition of the U.S. Drought Monitor had Iowa 100% free of even an 'abnormally dry' designation for the first time since July 12, 2011. Little, if any, rain fell across much of east central and southeast Iowa during the last one-half of the month. Monthly rain totals varied from 1.35 inches at Rock Rapids to 8.63 inches near Norwalk. At Denison above normal rainfall each month from April through September, including a record wet calendar month in August, has pushed their annual precipitation total through September 30 to 45.74 inches. With three months to go in the year, this breaks their previous annual record of 45.08 inches set in 1993 (115 years of data).

Cooling Degree Day Totals. Home air conditioning requirements, as estimated by cooling degree day totals, averaged 26% less than normal and 59% less than during the very warm September of 2013. Air conditioning requirements for the 2014 season are running 15% less than normal and 22% less than last year.

Summer Summary Summer temperatures averaged 70.2° or 1.4° below normal while precipitation averaged 19.31 inches or 5.60 inches above normal. This ranks as the 28th coolest and 4th wettest summer among 142 years of records.

The following is the number of new daily records set at COOP sites based on data back to 1951.

                 __________2014_____________________________2013_
                 SEP  AUG  JUL  JUN  MAY  APR  MAR  FEB  JAN  DEC
Maximum High:     25   25    4   27   79  118   24   26   79   21
Minimum High:    267  161  399   37  235  174  406  306  219  141
Maximum Low:      86  113    8  122  102   40    7    7   22   14
Minimum Low:     180   33  330   58  171  209  439  379  194  177
Maximum Precip:  176  182  134  342   92  187   29   91   36   41

The following is some bulk statistics on how well IEM's daily COOP data estimator is performing on a monthly basis versus this QC'd dataset.

                 ___________2014_______________________________
                 SEP   AUG   JUL   JUN   MAY   APR   MAR   FEB
High Temp Bias   0.2   0.0   0.2   0.1   0.2   0.4   1.3   1.4
High Temp RMSE   0.8   0.7   0.8   0.7   0.8   0.8   1.8   1.7
Low  Temp Bias   0.2   0.1   0.2   0.1   0.1   0.2   2.1   2.7
Low  Temp RMSE   0.9   0.8   1.0   0.8   0.9   1.0   2.4   2.9
Precip    Bias   0.33  0.39  0.2   0.13  0.20  0.14  0.36  0.31
Precip    RMSE   0.75  1.11  0.92  1.39  0.64  0.63  0.46  0.56

2660 Views August COOP Data Uploaded

Link: http://mesonet.agron.iastate.edu/climodat/

The quality controlled Iowa COOP data for August 2014 has been uploaded to the IEM. These observations are kindly provided by Harry Hillaker, our state climatologist, who passes along these notes on the month:

General Summary. Iowa temperatures averaged 71.4°, 0.1° below normal, while precipitation averaged 5.99 inches or 1.79 inches above normal.   This ranks 57th coolest and 14th wettest among 142 years of data.

Temperatures. The unseasonably cool weather of July continued through the first 16 days of August with only one day (4th) during the period averaging warmer than normal.   The second half of the month was just the opposite with only one day (27th) not averaging above the daily norm.   Temperature extremes were minimal during August with a range from a low of 47° at Chariton and Stanley on the 13th to a high of 95° at Donnellson on the 25th.   Numerous locations, particularly across the northern one-third of the state, have yet to reach ninety degrees this year.

Precipitation. The relatively dry weather pattern that began in early July gradually came to an end for most of Iowa during August.   Widespread rain fell across the southwest one-half of the state on the 6th-7th and 15th-16th.   Parts of northeast Iowa finally began seeing significant rain on the 18th with rain becoming nearly a daily occurrence statewide beginning on the 21st.   August rainfall was excessive over a wide area from west central into south central Iowa with monthly totals over ten inches.   At Greenfield (17.95 inches, old record 14.66 in July 1915) and Denison (12.65”, old record 12.39 in June 1967) August was the wettest calendar month on record while these same locations also experienced their wettest summer and wettest year-to-date.   A summary of records includes:
Wettest August:
Station2014Old RecordPeriod of Record
Greenfield17.9512.63 in 1977114 years
Denison12.659.75 in 1910122 years
Harlan12.599.85 in 1952115 years
Sioux City10.129.07 in 2007136 years
Wettest Summer:
Greenfield31.8526.79 in 1993113 years
Sioux City30.3820.12 in 2010135 years
Denison28.5724.47 in 1993122 years
Harlan26.7224.66 in 2010115 years
Le Mars22.3620.87 in 2010122 years
Wettest Year-To-Date:
Greenfield44.2038.89 in 1993110 years
Denison40.1738.19 in 1993115 years
Sioux City35.6336.72 in 1881130 years

On the other end of the spectrum, portions of the northeast one-half of the state recorded below normal rainfall in August.    East central Iowa was particularly dry with Anamosa recording only 1.43 inches.

Cooling Degree Day Totals. Home air conditioning requirements, as estimated by cooling degree day totals, averaged 12% less than last August and 4% less than normal.   Totals for the 2014 season-to-date are running 15% less than last year at this time and 14% less than normal.

Summer Summary Summer temperatures averaged 70.2° or 1.4° below normal while precipitation averaged 19.31 inches or 5.60 inches above normal.   This ranks as the 28th coolest and 4th wettest summer among 142 years of records.

The following is the number of new daily records set at COOP sites based on data back to 1951.

                 __________2014__________________________2013____
                 AUG  JUL  JUN  MAY  APR  MAR  FEB  JAN  DEC  NOV
Maximum High:     25    4   27   79  118   24   26   79   21   18
Minimum High:    161  399   37  235  174  406  306  219  141  170
Maximum Low:     113    8  122  102   40    7    7   22   14   25
Minimum Low:      33  330   58  171  209  439  379  194  177  241
Maximum Precip:  182  134  342   92  187   29   91   36   41  123

The following is some bulk statistics on how well IEM's daily COOP data estimator is performing on a monthly basis versus this QC'd dataset.

                 ___________2014_______________________________
                 AUG   JUL   JUN   MAY   APR   MAR   FEB   JAN
High Temp Bias   0.0   0.2   0.1   0.2   0.4   1.3   1.4   0.8
High Temp RMSE   0.7   0.8   0.7   0.8   0.8   1.8   1.7   1.3
Low  Temp Bias   0.1   0.2   0.1   0.1   0.2   2.1   2.7   1.4
Low  Temp RMSE   0.8   1.0   0.8   0.9   1.0   2.4   2.9   1.6
Precip    Bias   0.39  0.2   0.13  0.20  0.14  0.36  0.31  0.49
Precip    RMSE   1.11  0.92  1.39  0.64  0.63  0.46  0.56  0.59

2900 Views July COOP Data Uploaded

Link: http://mesonet.agron.iastate.edu/climodat/

The quality controlled Iowa COOP data for July 2014 has been uploaded to the IEM. These observations are kindly provided by Harry Hillaker, our state climatologist, who passes along these notes on the month:

General Summary. Temperatures averaged 69.0° or 4.6° below normal while precipitation totaled 3.43 inches or 1.07 inches below normal.   This ranks as the fifth coolest and 67th driest July among 142 years of state records.   A cooler July was last recorded just five years ago.   While precipitation was below normal it was much greater than during the previous two Julys.

Temperatures. Below normal temperatures were the rule through most of the month with just six days (6th-7th, 12th, 21st-22nd and 26th) averaging warmer than usual.   Overnight lows in the forties were just as frequent as daytime highs in the nineties.    The month’s lowest temperatures were 44 degree minimums on the morning of the 16th at Little Sioux and Stanley while daytime highs reached only 62 degrees at Allerton and Rathbun Dam on the 2nd.   Summer heat did creep into southwestern Iowa on the 21st, 22nd and 25th with heat indices soaring to 117° at Audubon on the 21st and Shenandoah on the 25th (actual temperature of 93° with a dew point of 82° both times).   Sidney recorded the highest actual temperature during the month with a 98° reading on the 25th.   Several locations across northern and eastern Iowa have yet to reach 90 degrees this year.   At Burlington this is the first time that temperatures have not reached 90° by the end of July since records began in 1897.

Precipitation. The month began with widespread flooding in progress from frequent heavy rains in late June.   However, July brought much less rain with only three events bringing a statewide average rainfall of more than one-half inch (0.73 inches on the 5th-6th, 0.80 on the 11th-12th and 0.56 on the 24th-25th).   Monthly rain totals were much below normal over parts of southwest and far northern Iowa.   Atlantic reported the lowest total with 0.75 inches while Montezuma reported the most with 10.21 inches.   Mild temperatures and abundant subsoil moisture reserves allowed the statewide average corn and soybean ratings to improve slightly during the month despite the drier weather.   Pasture conditions declined very slightly during July but remained much better than usual for late July according to USDA NASS numbers.

Cooling Degree Day Totals. Home air conditioning requirements, as estimated by cooling degree day totals, averaged 42% less than last July and 46% less than normal.   Cooling degree day totals so far this year are running 16% less than last year and 19% less than normal.

Severe Weather. Unlike the previous month, July 2014 was a quiet month for severe weather.   There were only a few dates with relatively isolated severe thunderstorms.   Nevertheless, the evening of July 6 brought nine small tornadoes to central Iowa.

The following is the number of new daily records set at COOP sites based on data back to 1951.

                 _____2014__________________________2013_________
                 JUL  JUN  MAY  APR  MAR  FEB  JAN  DEC  NOV  OCT
Maximum High:      4   27   79  118   24   26   79   21   18   31
Minimum High:    399   37  235  174  406  306  219  141  170   60
Maximum Low:       8  122  102   40    7    7   22   14   25   46
Minimum Low:     330   58  171  209  439  379  194  177  241   70
Maximum Precip:  134  342   92  187   29   91   36   41  123  138

The following is some bulk statistics on how well IEM's daily COOP data estimator is performing on a monthly basis versus this QC'd dataset.

                 _____2014_______________________________2013__
                 JUL   JUN   MAY   APR   MAR   FEB   JAN   DEC
High Temp Bias   0.2   0.1   0.2   0.4   1.3   1.4   0.8   0.7
High Temp RMSE   0.8   0.7   0.8   0.8   1.8   1.7   1.3   1.0
Low  Temp Bias   0.2   0.1   0.1   0.2   2.1   2.7   1.4   1.3
Low  Temp RMSE   1.0   0.8   0.9   1.0   2.4   2.9   1.6   1.6
Precip    Bias   0.2   0.13  0.20  0.14  0.36  0.31  0.49  0.24
Precip    RMSE   0.92  1.39  0.64  0.63  0.46  0.56  0.59  0.31

3762 Views June COOP Data Uploaded

Link: http://mesonet.agron.iastate.edu/climodat/

The quality controlled Iowa COOP data for June 2014 has been uploaded to the IEM. These observations are kindly provided by Harry Hillaker, our state climatologist, who passes along these notes on the month:

General Summary. Temperatures averaged 70.3° or 0.6°above normal while precipitation totaled 9.89 inches or 4.87 inches above normal.   This ranks as the 55th warmest and 3rd wettest June among 142 years of records.   The only calendar months with greater statewide precipitation averages were July 1993 (10.50”), June 2010 (10.39) and June 1947 (10.33).

Temperatures. Below normal temperatures prevailed on only nine days during the month, with the second week of June being especially cool.   Temperatures were above normal on all but two days over the last 16 days of the month but excessive heat never developed.   Temperatures reached into the nineties at only 21% of the reporting stations during the month with most of those in southwest Iowa.   The month’s highest temperatures were 93° readings at Sidney on the 18th and Little Sioux on the 20th.    Battle Creek reported the lowest temperature with 38° on the 13th.   A lower temperature had not been recorded so late in the season in Iowa since Cresco saw 35° on June 21, 1992.

Precipitation. Iowa came into June with much of the state in need of additional rainfall to replenish soil moisture reserves depleted by the very dry second one-half of 2013.  The wait for rain was quickly over with precipitation falling across all but extreme southeast Iowa on June 1st with locally heavy rain in portions of far northwest Iowa where Cherokee picked up 4.11 inches.   Rain also fell across all but far northeast Iowa on the 3rd with torrential rain falling across a sizable swath of southwest Iowa with Lamoni Airport recording 5.65 inches.   There was a welcome break in the rain until the 14th when excessive rain fell over much of northwest Iowa on the 14th-15th with Correctionville seeing 6.47 inches of rain.   Similar rains fell over the same areas of northwest Iowa on the 16th-17th with heavy rain also extending eastward through most of the northern one-half of the state.   Peterson reported the most rain with this event with 5.12 inches.   Record flooding commenced after this second major northwest Iowa rain event along the Rock and Big Sioux Rivers.   The rain focus then shifted to eastern Iowa with heavy rains on the 18th-19th including 5.12 inches at Postville.   Additional heavy rain totals included 4.27 inches near Council Bluffs on the 20th-21st, 5.45 inches near Adel on the 26th-27th and 6.11 inches at Muscatine on the 30th.   Monthly rain totals varied from 5.61 inches at Chariton to 17.00 inches at Cherokee.   An automated National Weather Service rain gage at Moville in Woodbury County recorded 18.70 inches of rain during June.   Record maximum rain totals for any calendar month were set at:
StationJune 2014 Total (inches)Old Record Period of Record
Cherokee17.0013.11 in Jun 201095 years
Emmetsburg16.6615.35 in Aug 200773 years
SiouxCity AP16.6511.78 in May 1903136 years
Sioux Rapids16.5111.72 in Aug 197572 years
Rock Rapids15.8610.98 in Jun 1984115 years
Le Mars15.3112.47 in Aug 1985125 years
Holstein14.2013.42 in Jun 196781 years
Sanborn13.9112.28 in Jun 1891102 years
Orange City12.0611.97 in May 2013110 years


Cooling Degree Day Totals. Home air conditioning requirements, as estimated by cooling degree day totals, averaged 7% greater than last June and 8% greater than normal.   Air conditioning requirements for the year to date are running 14% greater than last year at this time and 12% greater than normal.

Severe Weather. Severe thunderstorms were reported on 15 dates during June with three major outbreaks on the 3rd, 16th and 30th.   The first large severe weather outbreak brought high winds and large hail to 12 southwest Iowa counties on the 3rd and was an extension of a much larger event across Nebraska.   Severe storms, mostly high wind events, were reported from 46 Iowa counties on the 16th with most coming over the northeast one-half of the state.   The final major event was on the 30th with 43 Iowa counties reporting large hail and/or high winds from northeastern Nebraska across the central one-third of the state and on into northern Illinois and southern Wisconsin.   Overall there were 31 confirmed tornadoes during the month, the largest monthly total in Iowa since 2008, but only one exceeded EF-1 intensity.

The following is the number of new daily records set at COOP sites based on data back to 1951.

                 2014__________________________2013______________
                 JUN  MAY  APR  MAR  FEB  JAN  DEC  NOV  OCT  SEP
Maximum High:     27   79  118   24   26   79   21   18   31  364
Minimum High:     37  235  174  406  306  219  141  170   60    9
Maximum Low:     122  102   40    7    7   22   14   25   46  213
Minimum Low:      58  171  209  439  379  194  177  241   70   32
Maximum Precip:  342   92  187   29   91   36   41  123  138   82

The following is some bulk statistics on how well IEM's daily COOP data estimator is performing on a monthly basis versus this QC'd dataset.

                 2014_______________________________2013_______
                 JUN   MAY   APR   MAR   FEB   JAN   DEC   NOV
High Temp Bias   0.1   0.2   0.4   1.3   1.4   0.8   0.7   1.1
High Temp RMSE   0.7   0.8   0.8   1.8   1.7   1.3   1.0   1.3
Low  Temp Bias   0.1   0.1   0.2   2.1   2.7   1.4   1.3   1.2
Low  Temp RMSE   0.8   0.9   1.0   2.4   2.9   1.6   1.6   1.5
Precip    Bias   0.13  0.20  0.14  0.36  0.31  0.49  0.24  0.09
Precip    RMSE   1.39  0.64  0.63  0.46  0.56  0.59  0.31  0.28

4405 Views May COOP Data Uploaded

Link: http://mesonet.agron.iastate.edu/climodat/

The quality controlled Iowa COOP data for May 2014 has been uploaded to the IEM. These observations are kindly provided by Harry Hillaker, our state climatologist, who passes along these notes on the month:

General Summary. Temperatures averaged 60.1°, right at normal, while precipitation totaled 3.14 inches or 1.42 inches below normal. This ranks as the 66th warmest and 40th driest May among 142 years of records.

Temperatures. May began with five consecutive cooler than normal days and ended with nine consecutive warmer than normal ones. In between there was plenty of variety. A light freeze was recorded in a few scattered areas on the 2nd and 3rd. A brief, but very strong, warm-up prevailed on the 7th and 8th. Particularly noteworthy were temperatures soaring into the mid 90's in southwest Iowa on the afternoon of the 7th. Clarinda, Shenandoah and Sidney reached 97°, the highest temperatures recorded so early in the year in Iowa since Logan reached 99° on April 18, 1994. However, temperatures were far below normal from 14th to the 17th with freezes recorded somewhere in the state each day in the period. The coldest morning over most of western and central Iowa came on the 16th with a hard freeze occurring over much of northwest Iowa where Spencer Airport recorded a low of 24°. A lower temperature has not occurred so late in the season in Iowa since Sanborn reached 22° on May 22, 1963. There were reports of freeze-damaged soybeans needing to be replanted as far south as the Missouri border. Parts of eastern Iowa recorded their lowest temperatures of the month on the morning of the 17th with Stanley (Buchanan Co.) recording a low of 28°. Temperatures were frequently in the eighties after the 18th, but the highest late-month readings only reached the 90° mark on the 31st at Davenport, Iowa City, Lowden and Sioux Center.

Precipitation. Rain was relatively frequent during May but amounts fell short of normal over most of Iowa. A little more than one-half of the monthly rain total came on the 11th-12th when rain fell statewide and two to three inch totals were common over west central and southwest Iowa (maximum reported amount of 4.08 inches near Osceola). Rain was also widespread on the 25th-27th but large totals were confined to a small portion of west central Iowa where Holly Springs (Woodbury County) reported 4.72 inches. Monthly precipitation totals varied from 0.72 inches at Keosauqua to 8.33 inches near Castana. Unusually dry conditions prevailed across the northwest and southeast corners of Iowa during May. At Keosauqua this was their driest May among 127 years of record (old May record 1.00 in 1934). At Sibley in northwest Iowa this was the driest May since 1963 while at Rock Rapids this has been the driest year-to-date since 1963. The dry weather, along with late month warmth, allowed crop planting to progress ahead of the normal pace by June 1 after a very slow start to the season.

Heating Degree Day Totals. Home heating requirements, as estimated by heating degree day totals, averaged 8% less than last May but were 9% greater than normal. Degree day totals for the 2013-2014 season totaled 11% greater than last season and 14% greater than normal to make this the coldest heating season in 35 years.

Severe Weather. There were numerous episodes of severe weather during May, but overall activity was a little less widespread than is typical for May. The largest severe weather event came on the afternoon and evening of the 11th when severe storms were reported from 25 counties, mostly in southern Iowa, with a total of eight tornadoes. The most damaging storm was an EF-2 tornado striking Lake Panorama in Guthrie County shortly after sunset.

Spring Summary. The three spring months of March, April and May averaged 45.5° or 2.8° below normal while precipitation totaled 8.80 inches or 1.42 inches less than normal. This ranks as the 32nd coolest and 68th driest spring among 142 years of record. This season was uneventful compared to the two previous springs with 2012 setting a record for warmest spring and 2013 being the wettest on record.

The following is the number of new daily records set at COOP sites based on data back to 1951.

                 2014__________________________2013______________
                 MAY  APR  MAR  FEB  JAN  DEC  NOV  OCT  SEP  AUG
Maximum High:     79  118   24   26   79   21   18   31  364  160
Minimum High:    235  174  406  306  219  141  170   60    9  102
Maximum Low:     102   40    7    7   22   14   25   46  213  183
Minimum Low:     171  209  439  379  194  177  241   70   32   96
Maximum Precip:   92  187   29   91   36   41  123  138   82   44

The following is some bulk statistics on how well IEM's daily COOP data estimator is performing on a monthly basis versus this QC'd dataset.

                 2014_______________________________2013_______
                 MAY   APR   MAR   FEB   JAN   DEC   NOV   OCT
High Temp Bias   0.2   0.4   1.3   1.4   0.8   0.7   1.1   0.2
High Temp RMSE   0.8   0.8   1.8   1.7   1.3   1.0   1.3   0.7
Low  Temp Bias   0.1   0.2   2.1   2.7   1.4   1.3   1.2   1.4
Low  Temp RMSE   0.9   1.0   2.4   2.9   1.6   1.6   1.5   1.7
Precip    Bias   0.20  0.14  0.36  0.31  0.49  0.24  0.09  0.18
Precip    RMSE   0.64  0.63  0.46  0.56  0.59  0.31  0.28  0.59

4623 Views April COOP Data Uploaded

Link: http://mesonet.agron.iastate.edu/climodat/

The quality controlled Iowa COOP data for April 2014 has been uploaded to the IEM. These observations are kindly provided by Harry Hillaker, our state climatologist, who passes along these notes on the month:

General Summary. Temperatures averaged 47.2° or 1.7° below normal while precipitation totaled 4.83 inches or 1.32 inches above normal.   This ranks as the 43rd coolest and 12th wettest April among 142 years of records.   This was the seventh consecutive cooler than normal month and tenth consecutive wetter than normal April.

Temperatures. April temperatures were much closer to normal than recent months but cooler than typical weather was again predominant with below normal readings outnumbering above normal ones by 18 days to 12.   The year’s first 80 degree readings were recorded in a few western areas on the 9th with a maximum of 83° at Sioux City.   The month’s highest temperatures were recorded just a few days later with Clarinda, Des Moines and Indianola reaching 86° on the 12th.   On the other extreme Sanborn reported a minimum temperature of 11° on the morning of the 15th.   The last remnants of frozen soil finally thawed across northern Iowa about April 22.

Precipitation. Winter-like weather returned to the state after a mild last few days of March with accumulating snow falling across the northwest one-half of Iowa on the 3rd-4th.   Greatest snow totals were reported at Lake Park, Dickinson Co. (9.7 inches) and near Cleghorn, Cherokee Co. (9.0 inches).  For much of the far northwest corner of the state this snow storm was the largest precipitation event of the month and largest snow event of the winter.   Moderate to heavy precipitation covered all but far northwest Iowa from the 12th to the 14th.   Storm total rainfall exceeded four inches in a few areas from south central into northeast Iowa with 5.42 inches at Ladora (Iowa Co.) and 5.20 inches at Pella.   This was the state’s largest precipitation event since late May 2013.   The rain turned to snow over most of the state with light accumulations over the northwest one-half of Iowa.   Finally, a very slow moving storm brought substantial moisture to nearly all of Iowa from the 27th into May 1st.   Rain totals with this late month storm system reached 4.42 inches at Bondurant (Polk Co.) and 4.30 inches at Maxwell (Story Co.).   Snow also accumulated across parts of north central Iowa on the 29th-30th with 2.3 inches at Elma (Howard Co.) and 2.2 inches at Saint Ansgar (Mitchell Co.).   Monthly precipitation totals varied from 1.25 inches at Rock Rapids, their lowest April total since 1996, to 9.10 inches at Pella, their second largest April total among 87 years of record (10.04” in 1991).   The statewide average snowfall was 1.9 inches or 0.3 inches above normal to rank as the 37th snowiest April among 127 years of records.

Heating Degree Day Totals. Home heating requirements, as estimated by heating degree day totals, averaged 17% less than last April but 8% more than normal.   Degree day totals so far this heating season (since July 1, 2013) are running 11% greater than last season at this time and 14% greater than normal.

Severe Weather. There were two severe weather outbreaks during the month.   The most widespread event was on the 12th with large hail or high winds reported from 44 counties across the southeastern two-thirds of the state.   The second event brought high winds to 17 southeastern Iowa counties on the afternoon of the 27th.   This second event brought an EF1 tornado that tracked 46 miles across four counties from just north of Ottumwa to just west of Iowa City and resulted in two fatalities at separate locations in Keokuk County. Chariton.

The following is the number of new daily records set at COOP sites based on data back to 1951.

                 2014_____________________2013___________________
                 APR  MAR  FEB  JAN  DEC  NOV  OCT  SEP  AUG  JUL
Maximum High:    118   24   26   79   21   18   31  364  160   13
Minimum High:    174  406  306  219  141  170   60    9  102  204
Maximum Low:      40    7    7   22   14   25   46  213  183   58
Minimum Low:     209  439  379  194  177  241   70   32   96  217
Maximum Precip:  187   29   91   36   41  123  138   82   44   51

The following is some bulk statistics on how well IEM's daily COOP data estimator is performing on a monthly basis versus this QC'd dataset.

                 2014________________________2013_____________
                 APR   MAR   FEB   JAN   DEC   NOV   OCT   SEP
High Temp Bias   0.4   1.3   1.4   0.8   0.7   1.1   0.2   0.2
High Temp RMSE   0.8   1.8   1.7   1.3   1.0   1.3   0.7   0.9
Low  Temp Bias   0.2   2.1   2.7   1.4   1.3   1.2   1.4   1.3
Low  Temp RMSE   1.0   2.4   2.9   1.6   1.6   1.5   1.7   1.8
Precip    Bias   0.14  0.36  0.31  0.49  0.24  0.09  0.18 -0.08
Precip    RMSE   0.63  0.46  0.56  0.59  0.31  0.28  0.59  0.46

4601 Views March COOP Data Uploaded

Link: http://mesonet.agron.iastate.edu/climodat/

The quality controlled Iowa COOP data for March 2014 has been uploaded to the IEM. These observations are kindly provided by Harry Hillaker, our state climatologist, who passes along these notes on the month:

General Summary. Temperatures averaged 29.3° or 6.6° below normal while precipitation totaled 0.83 inches or 1.32 inches less than normal. This ranks as the 22nd coldest and 11th driest March among 142 years of records. A colder March was recorded just last year while there has not been a drier March since 1994. Snowfall averaged 6.1 inches or 1.4 inches above normal to rank as the 52nd snowiest March among 127 years of records. As has been the case for most of the winter season eastern Iowa recorded the coldest/wettest weather while western Iowa was drier with more frequent reprieves from the cold.

Temperatures. The cold weather pattern that began in mid-October continued unabated through March as well. The first few days of the month were especially cold with temperatures averaging more than thirty degrees below normal on the 2nd and 3rd. Daytime high temperatures were below zero in many areas on the 1st and 2nd. Elkader and Decorah reported the month's lowest temperatures with -24° readings on the morning of the 3rd. Lower March temperature extremes have been recorded only three times (1948, 1960 and 1962) while the same -24° reading was last seen during the month on March 12, 1998. However there were no additional subzero temperatures after the 6th. Wind chill readings dipped as low as -37° at Mason City on the 2nd and -34° at Marshalltown on the 3rd. Only one day during the month (10th) averaged more than ten degrees warmer than normal. There have now been a total of only seven days since mid-October with temperatures averaging ten or more degrees above normal while 63 days in the period have been more than ten degrees below normal. Nevertheless, there were some sure signs of spring during the month. Temperatures reached into the 70's somewhere in Iowa on five days during the month with the first occurrence of the year coming on the 9th when Little Sioux reached 74°. The highest temperature was a 79° reading on the 31st at Clarinda and Shenandoah. Considerable frost remained in the ground at month's end across northern Iowa but soils finally thawed across most of southern Iowa over the last few days of March.

Precipitation. It was a rather dry month across Iowa. Only Tripoli and Decorah managed to exceed the normal precipitation for the month while Sidney experienced their driest March of record (0.04 inches, old record 0.07 in 1956 among 72 years of data). Glenwood and Shenandoah tied with 1956 for their lowest March precipitation totals. Monthly totals varied from 0.03 at Glenwood up to 2.21 inches at New Hampton. Snowfall totals varied from 0.3 inches at Hastings to 15.5 inches at New Hampton. The bulk of the month's precipitation fell in two events at opposite ends of March. Snow fell statewide on the 1st-2nd with three to five inches common from Spencer southeast to Keokuk with a maximum amount of 8 inches reported at Zearing in Story County. The other event on the 27th brought rain statewide (with a dusting of snow in the far northwest) with greatest amounts across the northeast with Coggon (Linn County) reporting 1.24 inches.

Heating Degree Day Totals. Home heating requirements, as estimated by heating degree day totals, averaged 2% less than last March but 22% more than normal. Degree day totals so far this heating season (since July 1, 2013) are running 14% greater than normal and last season's total. A colder heating season was last recorded 35 years ago.

Severe Weather. There were a handful of severe weather reports in south central Iowa on the afternoon of the 27th with a brief tornado reported near Chariton.

The following is the number of new daily records set at COOP sites based on data back to 1951.

                 2014_____________________2013___________________
                 MAR  FEB  JAN  DEC  NOV  OCT  SEP  AUG  JUL  JUN
Maximum High:     24   26   79   21   18   31  364  160   13   43
Minimum High:    406  306  219  141  170   60    9  102  204   97
Maximum Low:       7    7   22   14   25   46  213  183   58   50
Minimum Low:     439  379  194  177  241   70   32   96  217   53
Maximum Precip:   29   91   36   41  123  138   82   44   51  103

The following is some bulk statistics on how well IEM's daily COOP data estimator is performing on a monthly basis versus this QC'd dataset.

                 2014____________2013_________________________
                 MAR   FEB   JAN   DEC   NOV   OCT   SEP   AUG
High Temp Bias   1.3   1.4   0.8   0.7   1.1   0.2   0.2   0.2
High Temp RMSE   1.8   1.7   1.3   1.0   1.3   0.7   0.9   0.8
Low  Temp Bias   2.1   2.7   1.4   1.3   1.2   1.4   1.3   1.2
Low  Temp RMSE   2.4   2.9   1.6   1.6   1.5   1.7   1.8   1.6
Precip    Bias   0.36  0.31  0.49  0.24  0.09  0.18 -0.08  0.00
Precip    RMSE   0.46  0.56  0.59  0.31  0.28  0.59  0.46  0.50

3777 Views February COOP Data Uploaded

Link: http://mesonet.agron.iastate.edu/climodat/

The quality controlled Iowa COOP data for February 2014 has been uploaded to the IEM. These observations are kindly provided by Harry Hillaker, our state climatologist, who passes along these notes on the month:

General Summary. Temperatures averaged 12.5° or 11.5° below normal while precipitation totaled 1.56 inches or 0.51 inches above normal. This ranks as the 7th coldest and 25th wettest February among 142 years of records. A colder February was last recorded in 1979 and a colder calendar month in December 2000.

Temperatures. The cold weather pattern that began in Iowa in mid-October continued through February. Temperatures averaged below normal on all but five days (13th and 17th-20th) of the month. There were no days averaging as much as ten degrees above normal but were 18 days more than ten degrees colder than usual. Elkader reported the lowest temperature of the month with a -29° reading on the 11th. However, bitter cold prevailed even at the end of the month with a -20° temperature on the 28th at Cresco, with temperatures to fall even further in early March. Nevertheless, portions of western and southern Iowa enjoyed some brief respite from the cold at mid-month with readings climbing above 50 degrees in some areas on the 13th, 15th, 17th, 18th and 19th. The temperature at Sidney soared to 67 degrees on the afternoon of the 18th. However, the temperature has not exceeded 42° at Charles City, Northwood and Osage since November. Spencer Airport recorded the lowest wind chill of the month at -42° on the 10th. Heating Degree Day Totals. Home heating requirements, as estimated by heating degree day totals, averaged 27% greater than last February and 28% more than normal. Degree day totals thus far this heating season (since July 1, 2013) are running 18% greater than last season and 13% greater than normal.

Precipitation. Precipitation was much more frequent during February than for the prior two months. Monthly precipitation totals were above normal at most locations and well above normal over the parts of eastern Iowa. Totals varied from 0.49 inches at Holly Springs and Rock Rapids to 3.90 inches at Donnellson. A higher February total has been recorded only once (4.25 in 2001) at Donnellson since measurements began there in 1940. The month's largest precipitation event came on the 20th with a wide variety of weather across Iowa. This event began with rain in most areas but transitioned to moderate to heavy snow over much of the northwest one-half of the state. Greatest snow totals were reported from Algona, Britt, Clarion and Lake Mills with eight inches. Meanwhile unseasonably heavy rain fell across far southeast Iowa with Donnellson picking up 2.21 inches. Thunderstorms were common across the southeast one-half of the state with hail up to one inch in diameter reported in Linn, Union, Warren and Wayne counties. Blizzard conditions were reported across north central Iowa on the evening of the 20th with wind gusts to 55 mph at Mason City. Other than on the 20th, nearly all of the remainder of the month's precipitation fell as snow. Snow totals varied from 5.0 inches at Sheldon in the northwest to 29.2 inches at Keosauqua in the southeast. The Keosauqua snowfall is the highest total for any month at that location (previous record 26.5 inches in Feb. 2008 among 121 years of records). The statewide average snowfall was 14.9 inches or 8.1 inches more than normal. This was the sixth snowiest February among 127 years of records and the state's snowiest calendar month since December 2009.

Winter Summary. The three mid-winter months of December, January and February averaged 14.6° or 7.5° below normal while precipitation totaled 2.68 inches or 0.66 inches less than normal. This ranks as the 9th coldest and 46th driest winter among 141 years of records. A colder winter was last recorded in 1978-1979 and a drier winter in 2005-2006. Persistent cold, with subnormal temperatures prevailing since mid-October, has allowed the soil under sod to freeze two to three feet beneath the surface and under roadways to depths as great as five and one-half feet. Water main breaks have become common across the state.

The following is the number of new daily records set at COOP sites based on data back to 1951.

                 2014_____________________2013___________________
                 FEB  JAN  DEC  NOV  OCT  SEP  AUG  JUL  JUN  MAY
Maximum High:     26   79   21   18   31  364  160   13   43  169
Minimum High:    306  219  141  170   60    9  102  204   97  311
Maximum Low:       7   22   14   25   46  213  183   58   50   61
Minimum Low:     379  194  177  241   70   32   96  217   53  116
Maximum Precip:   91   36   41  123  138   82   44   51  103  302

The following is some bulk statistics on how well IEM's daily COOP data estimator is performing on a monthly basis versus this QC'd dataset.

                 2014______2013_______________________________
                 FEB   JAN   DEC   NOV   OCT   SEP   AUG   JUL
High Temp Bias   1.4   0.8   0.7   1.1   0.2   0.2   0.2   0.4
High Temp RMSE   1.7   1.3   1.0   1.3   0.7   0.9   0.8   0.9
Low  Temp Bias   2.7   1.4   1.3   1.2   1.4   1.3   1.2   0.8
Low  Temp RMSE   2.9   1.6   1.6   1.5   1.7   1.8   1.6   1.3
Precip    Bias   0.31  0.49  0.24  0.09  0.18 -0.08  0.00 -0.08
Precip    RMSE   0.56  0.59  0.31  0.28  0.59  0.46  0.50  0.53

2750 Views January COOP Data Uploaded

Link: http://mesonet.agron.iastate.edu/climodat/

The quality controlled Iowa COOP data for January 2014 has been uploaded to the IEM. These observations are kindly provided by Harry Hillaker, our state climatologist, who passes along these notes on the month:

General Summary. Temperatures averaged 14.0° or 5.4° below normal while precipitation totaled 0.46 inches or 0.46 inches less than normal. This ranks as the 35th coldest and 20th driest January among 142 years of records. A colder calendar month was last recorded in January 2010 and a drier one in November 2007.

Temperatures. A very persistent weather pattern prevailed through the month bringing the coldest air frequently to northeastern Iowa where temperatures averaged 6 to 10 degrees below normal.   Meanwhile occasional brief periods of strong southwesterly winds allowed quick warm-ups across the far west where temperatures averaged only 2 to 4 degrees below normal.   The statewide average daily temperature was twenty or more degrees below normal on the 2nd, 5th, 6th, 23rd, 27th and 28th.  Each of these cold episodes was accompanied by strong winds, resulting in wind chills falling to -34° or lower.   Wind chills bottomed out at -51° on the morning of the 6th at Mason City and Oelwein.   These were the lowest wind chills recorded in Iowa since January 2, 2010 when Estherville recorded a -53° reading.   Actual temperatures fell as low as -29° at Elkader on the morning of the 28th.    On the other extreme temperatures climbed to daily record highs of 65° at Little Sioux, Logan and Sioux City on the 19th.    However, persistent snow cover over the northeast counties did not allow temperatures to climb above 38 degrees during the month at Dubuque and Oelwein.

Heating Degree Days Home heating requirements, as estimated by heating degree day totals, averaged 18% greater than last January and 11% greater than normal.   Degree day totals so far this heating season (since July 1) have averaged 15% greater than one year ago and 9% greater than normal.   This has been the coldest start to the heating season in 17 years.

Precipitation. Precipitation was rather frequent during January, especially over northeast Iowa, but amounts were nearly always on the light side.   Fort Madison reported the largest storm total with 6.6 inches of snow on the 4th-5th.    Monthly snow totals varied from 1.0 inch at Glenwood (all of which fell on New Year’s Day) to 18.4 inches at Strawberry Point.   There was little if any snow cover over much of the southwest one-half of the state during January while the northeast one-quarter of Iowa has endured continuous snow cover since December 8, with a snow depth of 10 to 15 inches being common at month’s end.   January precipitation totals were below normal statewide excepting for a handful of northeast Iowa locations and varied from 0.04 inches at Shenandoah to 1.38 inches at Fayette.

Severe Weather. Despite the lack of heavy snow, high winds combined with relatively light snowfall to produce blizzard conditions over portions of central Iowa on the 16th and over northeast and east central areas on the 26th.   Prolonged cold weather, combined with little, if any, snow cover has allowed soils under sod to freeze to depths of 20 to 27 inches across the state by month’s end according to National Weather Service measurements.   Iowa DOT sensors show the ground under pavement to be frozen from three to four and one-half feet below the surface.   The deep frost has resulted in hundreds over water mains breaks across the state.   Meanwhile the prolonged cold has resulted in a record spike in propane prices owing to a combination of high demand and low supply.   Finally, January has been an exceptionally windy month.   At Des Moines wind gusts exceeded 40 mph on eight days during the month.   The average wind speed for the month was 13.5 mph.   Owing to changes in wind measurement equipment and procedures over the years it is difficult to make ‘apples to apples’ historical comparisons but at Des Moines this was the highest calendar month wind speed average since March 1986.

The following is the number of new daily records set at COOP sites based on data back to 1951.

                 2014_____________________2013___________________
                 JAN  DEC  NOV  OCT  SEP  AUG  JUL  JUN  MAY  APR
Maximum High:     79   21   18   31  364  160   13   43  169   28
Minimum High:    219  141  170   60    9  102  204   97  311  358
Maximum Low:      22   14   25   46  213  183   58   50   61   28
Minimum Low:     194  177  241   70   32   96  217   53  116  319
Maximum Precip:   36   41  123  138   82   44   51  103  302  226

The following is some bulk statistics on how well IEM's daily COOP data estimator is performing on a monthly basis versus this QC'd dataset.

                 2014______2013_______________________________
                 JAN   DEC   NOV   OCT   SEP   AUG   JUL   JUN
High Temp Bias   0.8   0.7   1.1   0.2   0.2   0.2   0.4   0.4
High Temp RMSE   1.3   1.0   1.3   0.7   0.9   0.8   0.9   0.8
Low  Temp Bias   1.4   1.3   1.2   1.4   1.3   1.2   0.8   1.2
Low  Temp RMSE   1.6   1.6   1.5   1.7   1.8   1.6   1.3   1.4
Precip    Bias   0.49  0.24  0.09  0.18 -0.08  0.00 -0.08 -0.39
Precip    RMSE   0.59  0.31  0.28  0.59  0.46  0.50  0.53  0.94

2294 Views December COOP Data Uploaded

Link: http://mesonet.agron.iastate.edu/climodat/

The quality controlled Iowa COOP data for December 2013 has been uploaded to the IEM. These observations are kindly provided by Harry Hillaker, our state climatologist, who passes along these notes on the month:

General Summary. Iowa temperatures averaged 17.3° or 5.6° below normal while precipitation totaled 0.65 inches or 0.69 inches below normal. This ranks as the 17th coolest and 32nd driest December among 141 years of records. A colder December was last recorded in 2000 and a drier one in 2004. Temperatures. December began with mild weather as temperatures averaged above normal for the first four days of the month with Shenandoah reaching 62° on the 2nd. However, cold weather was the rule for most of the month with temperatures averaging more than twenty degrees below normal on the 7th, 9th, 23rd and 24th. Osceola reported the lowest official temperature in the state with a -27° reading on the morning of the 24th while Sheldon had the lowest wind chill with a -38° reading on the morning of the 11th. Daytime high temperatures remained below zero in some areas on the 6th, 23rd, 29th and 31st. Much warmer air briefly edged into far western Iowa late in the month with daily record highs set on the 27th and 28th. A strong cold front, with northwest winds gusting to 61 mph, barreled into northwest Iowa during the afternoon of the 28th with the temperature at Sioux City falling from 62° at 3:07 p.m. to -3° at 8:43 the next morning (a 65° drop in less than 18 hours). The combination of cold weather and dry ground allowed soils to freeze to a depth of from 7 to 15 inches by month's end. Snow cover at month's end varied from little, if any, in the far southwest to 8 to 10 inches across the northeast. However, the mostly dry, fluffy snow has a low water content of under an inch liquid equivalent.

Heating Degree Day Totals. Home heating requirements, as estimated by heating degree day totals, averaged 27% greater than last December and 13% greater than normal. Thus far this heating season (since July 1), heating requirements are up 14% from last season and 8% from normal. This has been the coldest start to the heating season in 13 years.

Precipitation. Precipitation was relatively frequent across the state but amounts were mostly light. Monthly totals were below normal at all reporting points varying from 0.06 inches at Logan (their third lowest December total among 145 years of record) to 1.29 inches at Clinton and Wapello. The month's largest precipitation event came on the 21st-22nd with snow falling across the southeast two-thirds of Iowa. Greatest snow totals with this storm occurred in south central Iowa with nine inch totals at Blockton and Lamoni. Other notable events came on the 8th when snow fell statewide with a maximum total of 5.3 inches at Des Moines. Finally, a large winter storm just clipped the far southeast corner of Iowa on the 13th-14th with seven inches of snow at Keokuk. Monthly snow totals varied from only 0.9 inches at Holly Springs to 18.0 inches at Belle Plaine. The statewide average snowfall was 9.3 inches or one inch above normal. This ranks as the 33rd greatest December total among 127 years of records.

Annual Summary. The statewide average temperature for 2013 was 46.5° or 1.6° below normal while precipitation totaled 35.38 inches or 0.11 inches above normal. This ranks as the 25th coolest and 37th wettest year among 141 years of records. The year was noteworthy for a record wet April and May, as well as a very dry July through September period. Precipitation totals varied from 21.12 inches at Spirit Lake to 49.58 inches at Saint Ansgar.

The following is the number of new daily records set at COOP sites based on data back to 1951.

                 ____________________2013________________________
                 DEC  NOV  OCT  SEP  AUG  JUL  JUN  MAY  APR  MAR
Maximum High:     21   18   31  364  160   13   43  169   28    0
Minimum High:    141  170   60    9  102  204   97  311  358    9
Maximum Low:      14   25   46  213  183   58   50   61   28    0
Minimum Low:     177  241   70   32   96  217   53  116  319   35
Maximum Precip:   41  123  138   82   44   51  103  302  226   74

The following is some bulk statistics on how well IEM's daily COOP data estimator is performing on a monthly basis versus this QC'd dataset.

                 ______2013____________________________________
                 DEC   NOV   OCT   SEP   AUG   JUL   JUN   MAY
High Temp Bias   0.7   1.1   0.2   0.2   0.2   0.4   0.4   0.1
High Temp RMSE   1.0   1.3   0.7   0.9   0.8   0.9   0.8   0.8
Low  Temp Bias   1.3   1.2   1.4   1.3   1.2   0.8   1.2   1.2
Low  Temp RMSE   1.6   1.5   1.7   1.8   1.6   1.3   1.4   1.5
Precip    Bias   0.24  0.09  0.18 -0.08  0.00 -0.08 -0.39 -0.87
Precip    RMSE   0.31  0.28  0.59  0.46  0.50  0.53  0.94  1.28

1756 Views COOP Download Update

Link: http://mesonet.agron.iastate.edu/request/coop/fe.phtml

The web page that provides historical COOP data (both reported and recent estimated data by the IEM) has gotten a complete rewrite, so it warrants a note of caution here about its use. Please check over the data it provides and let us know of any issues you have with it.

The major new feature is the ability to append an arbitrary previous year onto the current year's data. The reason this was added is that some models want a complete year's worth of data. The download form allows you to optionally specify a previous year that should be appended onto this year's data. For example, you could request that data from 2013 be appended onto this year and the downloaded dataset will have 2013's data included as 2014 "observations" after today's date. Rewording, if today is 8 September 2014, data in the download for 9 September 2014 will actually be the data for 9 September 2013! Confused yet? :) Regardless, this is completely optional and not enabled by default.

As always, let us know of problems you encounter!

1065 Views November COOP Data Uploaded

Link: http://mesonet.agron.iastate.edu/climodat/

The quality controlled Iowa COOP data for November 2013 has been uploaded to the IEM. These observations are kindly provided by Harry Hillaker, our state climatologist, who passes along these notes on the month:

General Summary. Iowa temperatures averaged 33.6° or 3.0° below normal while precipitation totaled 1.63 inches or 0.42 inches less than normal. This ranks as the 37th coolest and 66th wettest November among 141 years of records.

Temperatures. A string of nine consecutive warmer than normal Novembers came to an end in 2013. The season's first subzero temperature was recorded at Spencer Airport on the morning of the 12th with a low of -1°. This was Iowa's lowest temperature for so early in the winter season since November 4, 1991. There were another five dates between the 22nd and 29th with lows falling to zero or lower somewhere in the state. This equaled the number of zero degree or lower dates in the previous twelve Novembers combined. Stanley reported the month's lowest temperature with a -5° reading on the 27th. On the other end of the spectrum temperatures reached into the seventies twice. Clarinda was the hot spot with a 72° maximum on the 16th while a handful of extreme eastern Iowa locations reached 71° on the 17th. Overall this was Iowa's coldest November since 2000.

Heating Degree Day Totals. Home heating requirements, as estimated by heating degree day totals, averaged 10% greater than normal and 21% greater than last November. Season-to-date totals (since July 1) are running 3% greater than normal and one year ago.

Precipitation. The month's largest precipitation event came on the 5th-6th when 2 to 4 inches of snow fell across extreme northwest Iowa and rain fell elsewhere. Over the southwest and northwest corners of the state this one event accounted for most of the month's precipitation. Light snow fell over all but far southwest Iowa on Veteran's Day. Showers and thunderstorms brought rain to all but extreme northwest Iowa on the 16th-17th. Light snow fell statewide on the 21st-22nd with greatest amounts around two inches falling from Audubon to Boone. Finally parts of central and east central Iowa saw snow on the 25th with a narrow band of 2 to 5 inches accumulating along the U.S. Highway 20 corridor from Iowa Falls to Dubuque. Monthly precipitation totals varied from 0.30 inches at Rock Rapids to 3.13 inches at Stanley. Above normal totals were mostly confined to northeast Iowa. Monthly snow totals varied from only trace amounts at a few points in southern and western Iowa to 8.0 inches at Strawberry Point. There was a statewide average of 1.6 inches of snow. This was 1.1 inches below normal and ranks 47th lowest November total among 127 years of records.

Fall Summary. Temperatures over the three fall months averaged 50.3° or 0.1° above normal while precipitation totaled 6.53 inches or 1.50 inches less than normal. This ranks as the 56th coolest and 53rd driest fall among 141 years of records.

The following is the number of new daily records set at COOP sites based on data back to 1951.

                 _______________2013________________________
                 NOV  OCT  SEP  AUG  JUL  JUN  MAY  APR  MAR  FEB
Maximum High:     18   31  364  160   13   43  169   28    0    0
Minimum High:    170   60    9  102  204   97  311  358    9   10
Maximum Low:      25   46  213  183   58   50   61   28    0    1
Minimum Low:     241   70   32   96  217   53  116  319   35    0
Maximum Precip:  123  138   82   44   51  103  302  226   74   82

The following is some bulk statistics on how well IEM's daily COOP data estimator is performing on a monthly basis versus this QC'd dataset.

                 ______2013____________________________________
                 NOV   OCT   SEP   AUG   JUL   JUN   MAY   APR
High Temp Bias   1.1   0.2   0.2   0.2   0.4   0.4   0.1   1.3
High Temp RMSE   1.3   0.7   0.9   0.8   0.9   0.8   0.8   1.6
Low  Temp Bias   1.2   1.4   1.3   1.2   0.8   1.2   1.2   2.5
Low  Temp RMSE   1.5   1.7   1.8   1.6   1.3   1.4   1.5   2.6
Precip    Bias   0.09  0.18 -0.08  0.00 -0.08 -0.39 -0.87 -0.56
Precip    RMSE   0.28  0.59  0.46  0.50  0.53  0.94  1.28  0.91

1426 Views September COOP Data Uploaded

Link: http://mesonet.agron.iastate.edu/climodat/

The quality controlled Iowa COOP data for September 2013 has been uploaded to the IEM. These observations are kindly provided by Harry Hillaker, our state climatologist, who passes along these notes on the month:

General Summary. Iowa temperatures averaged 66.9° or 3.7° above normal while precipitation totaled 2.05 inches or 1.33 inches less than normal. This ranks as the 19th warmest and 29th driest September among 141 years of records. A warmer September was last recorded in 2005 while this month's low precipitation total still exceeds the September totals of three of the past four years.

Temperatures. Higher than normal temperatures were the rule for most of September. Temperatures reached or exceeded 100° on the 7th, 9th and 10th. The highest readings were 102° temperatures recorded at Donnellson and Keokuk on the 9th. Not since September 9, 1955 (104° at Missouri Valley) had a higher reading been recorded in Iowa for so late in the year. This was also the first time that three September dates reached triple digits in Iowa since 1955, but was far from the record of ten such days recorded in September 1897. Daily temperatures averaged ten or more degrees above normal on the 7th-11th, 18th-19th and 26th-27th. Donnellson and Keosauqua each recorded 11 days with temperatures at or above 90° compared to a September normal of three such days. On the other extreme, Spencer, Battle Creek and Sheldon recorded morning lows of 32° on the 21st. This freeze occurred about one week earlier than usual for northwest Iowa but no crop damage was reported.

Cooling Degree Day Totals. Home air conditioning requirements, as estimated by cooling degree day totals, averaged 96% greater than last September and 83% greater than normal. Cooling degree day totals for the year-to-date are running 22% less than last year at this time, but 9% more than normal.

Precipitation. The very dry weather pattern that began in late June over much of Iowa continued through September in most areas. A very welcome period of frequent rainfall occurred between the 14th and the 19th with locally heavy rain falling in a band from southwest into east central Iowa. However, despite this period of precipitation, monthly totals were below normal except for a few southwestern Iowa locations. September totals varied from only 0.32 inches at Sioux Center to 7.14 inches near Hastings in Mills County. Sioux Center's total is the second lowest among 111 years of September data at that location (0.15" in 1899). Thanks to a record wet spring, year-to-date precipitation totals remain above normal over about the northeast one-half of Iowa with the state as a whole averaging nearly ten inches more precipitation this year than at the same point in 2012. Nevertheless, the July 1 to September 30 statewide average precipitation total of 5.38 inches is second only to 1947's total of 5.26 inches (normal for the period is 12.08 inches).

Severe Weather. The relatively quiet Iowa severe weather season continued through September. However, high winds, along with some large hail, were reported from 19 counties on the afternoon and evening of the 19th.

The following is the number of new daily records set at COOP sites based on data back to 1951.

                 _______________2013_________________________2012
                 SEP  AUG  JUL  JUN  MAY  APR  MAR  FEB  JAN  DEC
Maximum High:    364  160   13   43  169   28    0    0  157   87
Minimum High:      9  102  204   97  311  358    9   10   20    2
Maximum Low:     213  183   58   50   61   28    0    1   79   33
Minimum Low:      32   96  217   53  116  319   35    0    0    0
Maximum Precip:   82   44   51  103  302  226   74   82   93   91

The following is some bulk statistics on how well IEM's daily COOP data estimator is performing on a monthly basis versus this QC'd dataset.

                 ______2013____________________________________
                 SEP   AUG   JUL   JUN   MAY   APR   MAR   FEB
High Temp Bias   0.2   0.2   0.4   0.4   0.1   1.3   0.8   1.0
High Temp RMSE   0.9   0.8   0.9   0.8   0.8   1.6   1.1   1.3 
Low  Temp Bias   1.3   1.2   0.8   1.2   1.2   2.5   2.2   2.5
Low  Temp RMSE   1.8   1.6   1.3   1.4   1.5   2.6   2.3   2.6
Precip    Bias  -0.08  0.00 -0.08 -0.39 -0.87 -0.56 -0.14  0.01
Precip    RMSE   0.46  0.50  0.53  0.94  1.28  0.91  0.42  0.35

2258 Views July COOP Data Uploaded

Link: http://mesonet.agron.iastate.edu/climodat/

The quality controlled Iowa COOP data for July 2013 has been uploaded to the IEM. These observations are kindly provided by Harry Hillaker, our state climatologist, who passes along these notes on the month:

General Summary. Iowa temperatures averaged 72.4° or 1.2° below normal while precipitation totaled 1.76 inches or 2.74 inches less than normal. This ranks as the 30th coolest and 8th driest July among 141 years of state records.

Temperatures. The month began with four days of below normal temperatures with Atlantic and Chariton recording morning lows of 48° on the 1st. This was followed by five days of above normal readings topped off by 95° maximums on the 8th at Clarion, Hampton and Pocahontas. The remainder of the month was evenly divided between one long warm spell (14th-22nd) and an equally long cool spell (23rd-31st). The month's highest temperature was a 98° reading at Keokuk on the 19th while heat indices (the estimated 'feel' of the air by combining temperature and humidity) maxed out at 102° at Monticello on the 17th and Des Moines, Iowa City and Knoxville on the 19th. The last nine days of the month all averaged cooler than usual with particularly cool weather from the 27th to the 29th. Battle Creek in Ida County reported a morning low of 39° on the 27th while Cresco saw an afternoon high of only 58° the same day. Battle Creek's low represented the first occurrence of sub-40° weather in July in Iowa since July 7, 1984. Daily record low temperatures were set over most of Iowa on the 28th and over portions of the state on the 27th and 29th.

Cooling Degree Day Totals. Home air conditioning requirements, as estimated by cooling degree day totals, averaged 45% less than last July and 8% less than normal. Degree day totals so far this cooling season are running 41% less than last year at this time and 3% less than normal.

Precipitation. The big weather story of the month was precipitation, or the lack of it. Following seven consecutive months of above normal precipitation July turned very dry. There were a few small areas in north central and south central Iowa receiving above normal rainfall but most of the southwest one-half of the state was very dry. Rain totals for the month varied from 0.13 inches at Atlantic to 6.72 inches at Lake Mills. Record low July precipitation totals were recorded at:

CityJuly 2013Old July RecordPeriod of Record
Carroll0.18 inches0.23 inches in 1947127 years
Sac City0.20 inches0.35 inches in 1901137 years
Red Oak0.42 inches0.46 inches in 1959102 years

Atlantic's total was the second lowest for July at that location with just a trace recorded in 2012.

The following is the number of new daily records set at COOP sites based on data back to 1951.

                 ____________2013_________________________2012___
                 JUL  JUN  MAY  APR  MAR  FEB  JAN  DEC  NOV  OCT
Maximum High:     13   43  169   28    0    0  157   87  152   14
Minimum High:    204   97  311  358    9   10   20    2    0   61
Maximum Low:      58   50   61   28    0    1   79   33   61  104
Minimum Low:     217   53  116  319   35    0    0    0    0   87
Maximum Precip:   51  103  302  226   74   82   93   91   40   99

The following is some bulk statistics on how well IEM's daily COOP data estimator is performing on a monthly basis versus this QC'd dataset.

                 ______2013______________________________2012_
                 JUL   JUN   MAY   APR   MAR   FEB   JAN   DEC
High Temp Bias   0.4   0.4   0.1   1.3   0.8   1.0   1.0   0.3
High Temp RMSE   0.9   0.8   0.8   1.6   1.1   1.3   1.4   0.8
Low  Temp Bias   0.8   1.2   1.2   2.5   2.2   2.5   1.8   1.3
Low  Temp RMSE   1.3   1.4   1.5   2.6   2.3   2.6   2.1   1.8
Precip    Bias  -0.08 -0.39 -0.87 -0.56 -0.14  0.01 -0.07 -0.39
Precip    RMSE   0.53  0.94  1.28  0.91  0.42  0.35  0.24  0.42

2133 Views June COOP Data Uploaded

Link: http://mesonet.agron.iastate.edu/climodat/

The quality controlled Iowa COOP data for June 2013 has been uploaded to the IEM. These observations are kindly provided by Harry Hillaker, our state climatologist, who passes along these notes on the month:

General Summary. Iowa temperatures averaged 69.0° or 0.7° below normal while precipitation totaled 5.01 inches or 0.01 inches below normal. This ranks as the 55th coolest and 61st wettest June among 141 years of records. A cooler June has not been recorded since 2004.

Temperatures. The very cool spring weather pattern continued into the first ten days of June with temperatures averaging below normal each day. Elkader reported a low of 37° on the morning of the 3rd for Iowa's lowest temperature for so late in the season since 1998. The month's first 80 degree maximum temperature did not arrive until the 10th. However, only five of the remaining days of June averaged cooler than normal. Nevertheless, extreme heat was absent during the month with monthly maximum temperatures of only 94° recorded at Sioux City on the 21st and Muscatine on the 22nd. A lower statewide maximum temperature in June has been recorded only six times in the past century (most recently in 2008 at 92°).

Cooling Degree Days Totals. Home air conditioning requirements, as estimated by cooling degree day totals, averaged 1% less than normal and 25% less than last June. Thus far this season cooling degree day totals are running 2% greater than normal and 36% less than at this time last year.

Precipitation. The storm track shifted a bit further north in June, keeping the excessive rains confined to about the northeast one-third of the state. The month's largest event came from the 21st to the 23rd with Dorchester recording 8.99 inches of rain. Major flooding resulted along northeast Iowa rivers such as the Upper Iowa and the Turkey. A second major rain event on the 24th brought 6.80 inches of rain to Lowden and resulted in major flooding along the Wapsipinicon River. Rain totals for the month varied from 2.11 inches at Holly Springs (Woodbury County) and 2.22 inches near Albia to a whopping 14.48 inch total at Dorchester (but still shy of their June record total of 15.13 inches set in 2008). The persistent spring and early summer precipitation has allowed all of Iowa to be rated as drought-free by the U. S. Drought Monitor for the first time since early August 2011. According to Iowa Agricultural Statistics crop planting progress has been the slowest since 1993 with 4% of the soybean acreage, mostly in north central and northeast Iowa, still unplanted at month's end. The statewide average year-to-date precipitation total was a record for the first one-half of the year at 24.87 inches or 7.67 inches more than normal. The old record for January through June was 24.46 inches set in 2008 while 2012's total for the entire year was 26.54 inches.

Severe Weather. June was a more active month for severe weather in Iowa than earlier months this year, but still quieter than what is typical. The two largest events came on the 12th and 24th. Hail, high winds and tornadoes were reported across north central and northeast Iowa on the 12th with an EF-3 tornado touching down near Belmond. More widespread activity occurred on the 24th when high winds struck a wide area from southwest into central Iowa with a second area from south central to east central Iowa. Within the latter area an EF-1 tornado resulted in one fatality at Muscatine.

The following is the number of new daily records set at COOP sites based on data back to 1951.

                 _____2013_________________________2012__________
                 JUN  MAY  APR  MAR  FEB  JAN  DEC  NOV  OCT  SEP
Maximum High:     43  169   28    0    0  157   87  152   14   69
Minimum High:     97  311  358    9   10   20    2    0   61    7
Maximum Low:      50   61   28    0    1   79   33   61  104    3
Minimum Low:      53  116  319   35    0    0    0    0   87   57
Maximum Precip:  103  302  226   74   82   93   91   40   99   10

The following is some bulk statistics on how well IEM's daily COOP data estimator is performing on a monthly basis versus this QC'd dataset.

                 ______2013______________________________2012_
                 JUN   MAY   APR   MAR   FEB   JAN   DEC   NOV
High Temp Bias   0.4   0.1   1.3   0.8   1.0   1.0   0.3   1.0
High Temp RMSE   0.8   0.8   1.6   1.1   1.3   1.4   0.8   1.2
Low  Temp Bias   1.2   1.2   2.5   2.2   2.5   1.8   1.3   1.4
Low  Temp RMSE   1.4   1.5   2.6   2.3   2.6   2.1   1.8   1.9
Precip    Bias  -0.39 -0.87 -0.56 -0.14  0.01 -0.07 -0.39 -0.07
Precip    RMSE   0.94  1.28  0.91  0.42  0.35  0.24  0.42  0.19