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