This winter has certainly seemed more like the other seasons of the year rather than the brutal winters we remember from past years. The featured chart is another metric showing how few winter weather headlines have been issued by the National Weather Service so far this winter as compared with the past six years. The value shown represents the average number of winter weather advisories and warnings per county in Iowa. The values are partitioned each year for before and after 16 Feb periods, so there is still plenty of time for more winter storms.

Voting:
Good = 11
Bad = 0

Tags:   winter  

The featured chart presents the maximum period with temperatures below freezing based on hourly observations for Des Moines. The longest period this year is only a bit longer than three previous years. There is still plenty of winter season to go and as is shown by the bottom chart, there are longest streaks of the season that get started in February and even March. The forecast has been hinting at a return of winter to the state with chances of snow, but temperatures do not look that cold at least to early next week.

Voting:
Good = 13
Bad = 2

Tags:   winter   freezing  

The featured chart presents a comparison between the accumulated snowfall prior to and after Christmas. Only a handful of winters have seen less snowfall after Christmas than before. The chart also shows that not having much snow prior to 25 December does not limit the amount of snow after with some of the largest totals coming after just a few inches in the first period. Currently, a large winter storm is just to our southwest, but struggling to bring snow into Iowa. The chances for a white Christmas continue to look rather dim.

Voting:
Good = 26
Bad = 3

Tags:   winter   snow  

Yesterday's feature presented the climatology of the number of winter snow storms. The featured chart today presents the total snowfall for the winter season. The years with the maximum and minimum accumulation are shown as well. For the immediate future, our chances of rain look to be better than snow, but technically it is still the fall season and we have all of the winter season yet to go!

Voting:
Good = 21
Bad = 2

Tags:   winter   snow  

The featured chart presents a climatology of winter season snow storms for Des Moines. For this chart, a snow storm is defined as having at least one day with measurable snowfall followed by at least one day without snow. The years with the maximum and minimum number of storms are shown as well. With only a few storms in the books this year, we have plenty more to go.

Voting:
Good = 18
Bad = 4

Tags:   winter   snow  

Ames experienced its first day with a high temperature below freezing on Sunday. The featured chart presents the number of days each winter with a daily high temperature below freezing along with the first day of winter below freezing. The first day this year is a bit later than normal. The bottom chart hints that having the first frozen day in December typically leads to a below average number of frozen days for the winter season. If this were to happen, it would buck the recent trend shown in the middle figure of having above average number of days per year with a high temperature below freezing.

Voting:
Good = 14
Bad = 3

Tags:   frozen   winter  

Thursday morning saw our coldest temperatures of the season with lows approaching zero degrees in far northwest Iowa. The featured chart presents the average first date of occurrence for a given temperature for four sites in Iowa. It is interesting to see how much closer Ames is to Sioux City than Des Moines. Davenport's climatology is about two weeks later than Ames, so for example Ames hits its first sub freezing around mid October and Davenport is toward the end of October.

Voting:
Good = 23
Bad = 4

Tags:   winter  

A refreshing push of much warmer air make it into the state today and sure makes things feel much more like spring, but is the spring season actually here? If one thinks about winter as being the 91 (1/4 year) coldest days of the year, then perhaps spring has already arrived. The featured chart looks at the coldest (avg high+low) 91 day period for Ames and a fit line is placed on the end of the period. The fit would indicate that spring is coming a bit earlier than in the past. The colors of the bars represent the quartile of the average temperature for the winter season. A number of the bars push well into March, but the forecast for the next week looks very warm, so based on this metric, we are probably in spring now!

Voting:
Good = 11
Bad = 11

Tags:   winter  

While the lengthening days and warmer temperatures of March can make winter fell like it has gone away, the cold and snow of winter is still common in March. The featured chart presents the partitioning of yearly snowfall between dates prior to 1 March and those afterward. The 1to1 line shows that getter more snow after 1 March than before is rather uncommon, so our total so far of around 30 inches has little chance of being doubled this spring. Getting another 3-12 inches is common and the forecast this week looks to work on those totals with heavy snow possible in Iowa on Tuesday.

Voting:
Good = 17
Bad = 8

Tags:   snow   winter  

The three months of the year known as meteorological winter are now in the books and preliminary data shows that high and low temperatures were below average for the period. The featured chart presents these averages and the last four winters have been on the cold side. But now we can focus on March and hopes for a warm spring! March will begin like a lamb with highs in the 40s today.

Voting:
Good = 18
Bad = 3

Tags:   winter  

The temperature finally broke freezing on Thursday ending a modest streak of 9 days below. Earlier in January, we had a streak of 11 days which is the longest such streak this winter season. The featured chart presents the longest consecutive day streak below freezing for each winter since 1893. As with other charts recently featured, the winters of 77 and 78 stand out. The bottom chart shows the period during which the streaks of various lengths occurred. There is an interesting streak of 30 days that lasted from late February to mid March (1960). There is certainly plenty more time for cold weather this winter!

Voting:
Good = 27
Bad = 11

Tags:   winter   freezing  

Very cold temperatures and a bit of wind have conspired over night to bring bitterly cold wind chills to Iowa this Friday. The featured chart presents the reported wind chill against the air temperature during hours which the wind speed was measurable. Histograms of each are presented at the side and top. -20°F is roughly an observed threshold of wind chill where frequencies start declining at colder temperatures. Of course, the most extreme values are even more rare and often do not happen every year.

Voting:
Good = 44
Bad = 27

Tags:   windchill   winter  

Today is the winter solstice, when the daylight hours are the shortest for the year. Intuitively, one may expect this to be the coldest day of the year since it would have the least amount of sunshine. The featured map presents an analysis of the number of days after the solstice when the coldest day locally occurs. For Iowa, this works out being the middle of January. The east to west pattern over the United States is interesting as it takes a bit longer to cool the regions around the Great Lakes.

Voting:
Good = 24
Bad = 3

Tags:   winter   temp  

While yesterday was the start of meteorological winter, the 21st is the start of the commonly defined winter season. If one considers winter a 91 day period with the coldest climatological temperatures, the actual start of winter is slightly before 1 December in Iowa. The feature map presents an IEM produced analysis of the start date of the coldest 91 consecutive day period based on climatology data. The map nicely shows the start of this period comes first for those in the western US and marches east with a ~4 week difference between the two. The coastal regions of California enjoy the moderating effects of the Pacific Ocean and appear to be the last to join the winter period.

Voting:
Good = 31
Bad = 4

Tags:   winter   temp  

Today starts the meteorological winter season and one wonders if it will be as wet as recent winters. The featured chart presents the range of reported winter season precipitation for Iowa (bars) along with the totals for Ames and the mean state wide value. Of course, when these precipitation amounts fall in the form of snow or ice, it makes for a much more difficult winter. The chart interestingly shows that most of the time (~ 70%), the precipitation total in Ames is lower than the state wide average. This is probably due to having more rainfall events clip southeast Iowa.

Voting:
Good = 31
Bad = 5

Tags:   winter  

The mercury hit 70 degrees for places like Des Moines yesterday. The featured chart presents the time period each year between the last fall and first spring observation of 70+ degrees for Des Moines. The average period is 142 days and periods longer than that are shown in blue. The forecast has us comfortably in the 60s today but cooler weather expected later this week. We could be saying goodbye to the 70s until March!

Voting:
Good = 15
Bad = 5

Tags:   winter  

The featured map displays the number of hours this winter under a blizzard warning according to unofficial IEM stored data. Iowa has certainly seen its share of blizzard conditions this winter with locations shown in red over 30 hours of blizzard warning time. Hopefully these totals are not added to for the rest of the winter and the immediate term forecast would indicate so. The real barometer of the duration of winter left will be checking his shadow later this morning.

Voting:
Good = 23
Bad = 5

Tags:   winter  

The featured chart looks at the cumulative probability that by a given date, the min low, min high or maximum snowfall has occurred for the winter season. For example, by Jan 28th the lowest high temperature for the season occurred 75% of the time prior to the date (meaning the coldest highs are hopefully behind us). It is interesting to note the slope of the maximum snowfall line and how the current value is around 40%. Big snowfalls are still possible, especially as we transition to spring (imagine that).

Voting:
Good = 77
Bad = 13

Tags:   winter   climate  

While this has been a difficult winter for Iowa, how does it compare with past winters for the amount of winter we experience? While there is no one proper way to compute the misery for a winter, the featured graph shows a simple calculation of the total number of days for the winter below freezing and with snow cover (having both would count as 2 points) for Ames dating back to 1965. With this statistic, our recent few winters come up short compared with the winter of 2000-2001 and the winters of 1978 and 1979. Has this winter been the worst you have experienced? How do you quantify winter misery?

Voting:
Good = 21
Bad = 8

Tags:   winter  

The featured table presents the number of days that the high temperature was in a certain temperature range for meteorological winter (December, Januuary, and February). The year shown is the year of the December month of the period. This winter has seen its fair share of cold days and warm. It could have been worse like last year or even 1978. The chart also shows a few exceptional years in our recent past.

Voting:
Good = 27
Bad = 8

Tags:   winter  

The featured chart attempts to look at the frequency of having a second day of sub freezing high temperatures after a day below freezing. The red line represents the overall chance of having a below freezing high temperature. This plot would indicate that if a day was below freezing, it is likely (greater than 50% chance) that the next day would be below freezing. A warm up is expected this week before the next winter storm on Thursday.

Voting:
Good = 26
Bad = 13

Tags:   winter  

Wind Chill values are again running well below zero this morning with a good portion of the state under a wind chill advisory. How often are wind chill values this cold? The featured table displays the number of hours exceeding certain temperature thresholds. This winter (shown as 2008) has seen 15 hours of sub -30F, which is at the simple historical average of 15 based on data back to 1973. The brutal winters of 1978 and 1983 are shown as well for comparison.

Voting:
Good = 20
Bad = 6

Tags:   windchill   winter  

What makes this winter feel longer than others? There is no one way to prove this statement to be true, but we can sure compare this year to others. The featured chart shows the maximum consecutive days of having sub 50°F temperatures for Ames, which could be one way to quantify winter's apparent length. Most Iowans probably remember the brutal winter of 2000-2001, which was the longest streak. This winter is up to 86 days, which ranks just 26th in the climate history and 30 days longer than the average maximum winter streak. If you have any other ideas to quantify the statement, please let me know!

Voting:
Good = 22
Bad = 6

Tags:   winter  

The big story of the current winter storm is not the snowfall, but the bitter cold temperatures and wind that will make today and Friday very dangerous to be outside. The featured graph shows the percentage of years in Ames's climate history that a certain threshold low temperature was exceeded. According to this plot, Ames has seen a sub -20 °F temperature in 40% of years during the Dec, Jan, and Feb months. Lows on Saturday are only expected to reach -10 °F, which is common just about every year.

Voting:
Good = 26
Bad = 3

Tags:   winter