Past Features
This page lists out the IEM Daily Features for a month at a time. Features have been posted on most days since February 2002. List all feature titles.
Sun Mar 02, 2014
'13-'14 Winter Storm #24
02 Mar 2014 10:59 AM
Falling snow has finally moved south of Iowa this Sunday morning after lingering across the state since Friday. The featured map is an attempt at an analysis of reported snowfall for the entire event. Snow totals were highly variable with some locations getting over six inches, while others got less than an inch. The snow fell at very cold temperatures, so the wind was able to easily blow it around due to the lower water content. Even with the March sunshine today, temperatures will not be pleasant with afternoon highs struggling to reach 0! Record smashing cold is expected tonight with some locations flirting with all-time record cold lows for March.
Voting: Good - 45 Bad - 12
Tags: winter1314
02 Mar 2014 10:59 AM
Falling snow has finally moved south of Iowa this Sunday morning after lingering across the state since Friday. The featured map is an attempt at an analysis of reported snowfall for the entire event. Snow totals were highly variable with some locations getting over six inches, while others got less than an inch. The snow fell at very cold temperatures, so the wind was able to easily blow it around due to the lower water content. Even with the March sunshine today, temperatures will not be pleasant with afternoon highs struggling to reach 0! Record smashing cold is expected tonight with some locations flirting with all-time record cold lows for March.
Voting: Good - 45 Bad - 12
Tags: winter1314
Mon Mar 03, 2014
Smashing Record Lows
03 Mar 2014 08:42 AM
The Waterloo Airport reported a low temperature of -19 degrees this morning, which beat the previous record by 13 degrees! The featured chart presents the amount a newly set daily record temperature beat the previous record-to-date for that day for Waterloo. A thirteen degree beat for low temperature was the largest departure since 5 Dec 2005. Some of the extreme beats are labelled on this chart and you'll notice most of the dates are in the winter and spring months. Temperatures are more constrained in the summer time thanks to soil temperatures and atmospheric humidity, so it is much more difficult to get large beats of records during those months.
Voting: Good - 36 Bad - 6
Tags: highs lows records
Generate This Chart on Website
03 Mar 2014 08:42 AM
The Waterloo Airport reported a low temperature of -19 degrees this morning, which beat the previous record by 13 degrees! The featured chart presents the amount a newly set daily record temperature beat the previous record-to-date for that day for Waterloo. A thirteen degree beat for low temperature was the largest departure since 5 Dec 2005. Some of the extreme beats are labelled on this chart and you'll notice most of the dates are in the winter and spring months. Temperatures are more constrained in the summer time thanks to soil temperatures and atmospheric humidity, so it is much more difficult to get large beats of records during those months.
Voting: Good - 36 Bad - 6
Tags: highs lows records
Generate This Chart on Website
Tue Mar 04, 2014
Very cold for March
04 Mar 2014 05:38 AM
Our most recent bout with very cold winter air this season was rather exceptional considering that the calendar is now in March! The featured image shows hourly temperature reports from the Des Moines Airport for Sunday and early Monday along with the last observation that cold for that hour in March. Sunday afternoon was particularly cold as one would have to go back 50-65 years to experience similar temperatures. The good news is that warmer weather is in the forecast and we can only go up from here!
Voting: Good - 31 Bad - 4
Tags: mar
04 Mar 2014 05:38 AM
Our most recent bout with very cold winter air this season was rather exceptional considering that the calendar is now in March! The featured image shows hourly temperature reports from the Des Moines Airport for Sunday and early Monday along with the last observation that cold for that hour in March. Sunday afternoon was particularly cold as one would have to go back 50-65 years to experience similar temperatures. The good news is that warmer weather is in the forecast and we can only go up from here!
Voting: Good - 31 Bad - 4
Tags: mar
Wed Mar 05, 2014
'13-'14 Winter Storm #25
05 Mar 2014 11:26 AM
Far northeastern Iowa picked up a considerable amount of snowfall last night into this morning with totals well over six inches in some locations. Amounts quickly dropped off to the south of the highest totals. The good news is that warmer temperatures are on the way and the melting process can proceed!
Voting: Good - 14 Bad - 3
Tags: winter1314
05 Mar 2014 11:26 AM
Far northeastern Iowa picked up a considerable amount of snowfall last night into this morning with totals well over six inches in some locations. Amounts quickly dropped off to the south of the highest totals. The good news is that warmer temperatures are on the way and the melting process can proceed!
Voting: Good - 14 Bad - 3
Tags: winter1314
Thu Mar 06, 2014
Temps below average
06 Mar 2014 05:50 AM
The featured chart presents a time series of two week averaged Iowa temperature and precipitation departures since the beginning of December. This two week average is computed every seven days with the end of the two week period labelled on the graph. Nearly all points on this chart are in the negative temperature departure range with only the brief warmup period in mid January at a slightly positive departure. Our winter can be described as going from cold and dry to cold and wet! We're getting many snow storms in December, but they were not producing a lot of snowfall. Our recent stretch of winter has seen storm systems with more moisture to work with.
Voting: Good - 25 Bad - 2
Tags: cycles
Generate This Chart on Website
06 Mar 2014 05:50 AM
The featured chart presents a time series of two week averaged Iowa temperature and precipitation departures since the beginning of December. This two week average is computed every seven days with the end of the two week period labelled on the graph. Nearly all points on this chart are in the negative temperature departure range with only the brief warmup period in mid January at a slightly positive departure. Our winter can be described as going from cold and dry to cold and wet! We're getting many snow storms in December, but they were not producing a lot of snowfall. Our recent stretch of winter has seen storm systems with more moisture to work with.
Voting: Good - 25 Bad - 2
Tags: cycles
Generate This Chart on Website
Fri Mar 07, 2014
Plenty of time for snow
07 Mar 2014 05:40 AM
The warmer weather expected this weekend and early next week may have some hoping that winter is over. The featured chart presents the snowfall accumulation before and after March 6th each year. The top chart shows the percentage of the seasonal snowfall total that fell prior to 6 March each year. The bottom chart shows the snowfall total for after 6 March each year. The horizontal line on each chart displays the average and delivers the bad news that having more snowfall this season is likely. On average, we'd expect to get six more inches.
Voting: Good - 48 Bad - 16
07 Mar 2014 05:40 AM
The warmer weather expected this weekend and early next week may have some hoping that winter is over. The featured chart presents the snowfall accumulation before and after March 6th each year. The top chart shows the percentage of the seasonal snowfall total that fell prior to 6 March each year. The bottom chart shows the snowfall total for after 6 March each year. The horizontal line on each chart displays the average and delivers the bad news that having more snowfall this season is likely. On average, we'd expect to get six more inches.
Voting: Good - 48 Bad - 16
Mon Mar 10, 2014
First 60
10 Mar 2014 05:34 AM
Sunday was a welcome relief from winter as high temperatures pushed well above the freezing point for Iowa. Even warmer weather is expected today with some locations hitting 60 degrees for the first time this year. The featured map presents the average date of first 60 degree temperature for the year along with the locations that have seen 60+ degrees so far this year. The impact of significant snow cover over the eastern half of the domain can be seen as areas that should have seen 60+ by now have not. The climatological gradient over Iowa is interesting as a month of time is shown from southwestern Iowa to northeastern Iowa.
Voting: Good - 28 Bad - 2
Tags: 60 spring
10 Mar 2014 05:34 AM
Sunday was a welcome relief from winter as high temperatures pushed well above the freezing point for Iowa. Even warmer weather is expected today with some locations hitting 60 degrees for the first time this year. The featured map presents the average date of first 60 degree temperature for the year along with the locations that have seen 60+ degrees so far this year. The impact of significant snow cover over the eastern half of the domain can be seen as areas that should have seen 60+ by now have not. The climatological gradient over Iowa is interesting as a month of time is shown from southwestern Iowa to northeastern Iowa.
Voting: Good - 28 Bad - 2
Tags: 60 spring
Tue Mar 11, 2014
Obvious Relationship
11 Mar 2014 05:37 AM
After a wonderful Sunday, Monday was able to top it with temperatures soaring to levels not seen since last year. Sioux City was able to tie a record high temperature of 74 degrees. Not all of the state was able to get that warm and the sole reason was the deep snowpack that still exists over much of northeastern Iowa. The featured chart shows the obvious relationship between morning snow cover and the afternoon high temperature over Iowa for Monday. A forecasting rule of thumb states that the high temperature can not exceed 43 degrees when there is at least four inches of snow depth present in the morning, but this rule does not hold when significant warm air advection is happening. Warm air advection is the process of moving warmer air into areas with colder air. This warm air from the south helps to push temperatures even warmer.
Voting: Good - 24 Bad - 11
Tags: snowcover
11 Mar 2014 05:37 AM
After a wonderful Sunday, Monday was able to top it with temperatures soaring to levels not seen since last year. Sioux City was able to tie a record high temperature of 74 degrees. Not all of the state was able to get that warm and the sole reason was the deep snowpack that still exists over much of northeastern Iowa. The featured chart shows the obvious relationship between morning snow cover and the afternoon high temperature over Iowa for Monday. A forecasting rule of thumb states that the high temperature can not exceed 43 degrees when there is at least four inches of snow depth present in the morning, but this rule does not hold when significant warm air advection is happening. Warm air advection is the process of moving warmer air into areas with colder air. This warm air from the south helps to push temperatures even warmer.
Voting: Good - 24 Bad - 11
Tags: snowcover
Wed Mar 12, 2014
91 day coldest period
12 Mar 2014 05:40 AM
Has the winter season already passed us by? If one considers the coldest stretch of 91 days (1/4 of the year) to be the winter season, it is likely that we are now in spring as shown by the featured chart. It displays the 91 day lagging average temperature for this season along with the climatological average. This year's line has stopped its decline and has trended upward thanks to the recent warm weather. The highlighted area indicates the coldest 91 days and it would appear unlikely that we will be able to push any lower this month with decent temperatures in the forecast. This does not mean we are done with the snow storms as Iowa experiences plenty of these in March and April even while the temperatures warm. You also should not need reminding that it snowed in May 2013!
Voting: Good - 34 Bad - 4
12 Mar 2014 05:40 AM
Has the winter season already passed us by? If one considers the coldest stretch of 91 days (1/4 of the year) to be the winter season, it is likely that we are now in spring as shown by the featured chart. It displays the 91 day lagging average temperature for this season along with the climatological average. This year's line has stopped its decline and has trended upward thanks to the recent warm weather. The highlighted area indicates the coldest 91 days and it would appear unlikely that we will be able to push any lower this month with decent temperatures in the forecast. This does not mean we are done with the snow storms as Iowa experiences plenty of these in March and April even while the temperatures warm. You also should not need reminding that it snowed in May 2013!
Voting: Good - 34 Bad - 4
Thu Mar 13, 2014
Cold start to 2014
13 Mar 2014 05:37 AM
The featured map displays the 2014 rank for average temperature this year versus past years dating back to 1893. While locations in northeastern Iowa are in the top 10 coldest, the rest of the state has not faired as poorly. The difference has been the amount of snow cover, but the "chicken and egg" paradox applies. A number of the snow producing storm systems have tracked in a NW to SE fashion and mostly missed western Iowa. These storm tracks often delineate warm and cold air masses, so the cold areas get colder with increased snowfall and the warm areas get warmer with no snow cover. The forecast for today has a brief return to very warm temperatures, so our year to date totals will be getting warmer for today at least.
Voting: Good - 11 Bad - 3
13 Mar 2014 05:37 AM
The featured map displays the 2014 rank for average temperature this year versus past years dating back to 1893. While locations in northeastern Iowa are in the top 10 coldest, the rest of the state has not faired as poorly. The difference has been the amount of snow cover, but the "chicken and egg" paradox applies. A number of the snow producing storm systems have tracked in a NW to SE fashion and mostly missed western Iowa. These storm tracks often delineate warm and cold air masses, so the cold areas get colder with increased snowfall and the warm areas get warmer with no snow cover. The forecast for today has a brief return to very warm temperatures, so our year to date totals will be getting warmer for today at least.
Voting: Good - 11 Bad - 3
Fri Mar 14, 2014
Difference a week makes
14 Mar 2014 05:39 AM
It was only a week ago that we were climbing out of the deep freeze after highs on the second near zero! The weather this week has been much warmer with very seasonable highs on Thursday. The featured image compares the Aqua MODIS true color image from the past two Thursdays. The snow cover is now confined to northeastern Iowa after covering much of the state just a week ago. Unfortunately, there are chances of snow in the forecast and so we are not done with winter just yet!
Voting: Good - 43 Bad - 15
Tags: modis
14 Mar 2014 05:39 AM
It was only a week ago that we were climbing out of the deep freeze after highs on the second near zero! The weather this week has been much warmer with very seasonable highs on Thursday. The featured image compares the Aqua MODIS true color image from the past two Thursdays. The snow cover is now confined to northeastern Iowa after covering much of the state just a week ago. Unfortunately, there are chances of snow in the forecast and so we are not done with winter just yet!
Voting: Good - 43 Bad - 15
Tags: modis
Sun Mar 16, 2014
'13-'14 Winter Storm #26
16 Mar 2014 04:55 PM
Our recent stretch of warm weather and melting snow has been replaced by cold temperatures and a new snowfall. The highest totals from this latest bout with winter were over southeastern Iowa with two inches or less over much of the rest of the state. Sunshine on Sunday was able to make quick work of much of this snowfall and warmer temperatures are in the forecast for this week.
Voting: Good - 15 Bad - 5
Tags: winter1314
16 Mar 2014 04:55 PM
Our recent stretch of warm weather and melting snow has been replaced by cold temperatures and a new snowfall. The highest totals from this latest bout with winter were over southeastern Iowa with two inches or less over much of the rest of the state. Sunshine on Sunday was able to make quick work of much of this snowfall and warmer temperatures are in the forecast for this week.
Voting: Good - 15 Bad - 5
Tags: winter1314
Tue Mar 18, 2014
More than half below
18 Mar 2014 05:42 AM
Yesterday was yet another day with very pleasant high temperatures in western Iowa and much colder temps over the remaining snow cover in northeastern Iowa. The featured map presents an analysis of the percentage of days so far this year that have experienced below average daily high temperatures. The pattern over the Midwest is clear with the most number of above average days over the western portion. Yet another winter storm system is set to visit the region today with the heaviest snowfall totals expected north of Iowa.
Voting: Good - 17 Bad - 4
18 Mar 2014 05:42 AM
Yesterday was yet another day with very pleasant high temperatures in western Iowa and much colder temps over the remaining snow cover in northeastern Iowa. The featured map presents an analysis of the percentage of days so far this year that have experienced below average daily high temperatures. The pattern over the Midwest is clear with the most number of above average days over the western portion. Yet another winter storm system is set to visit the region today with the heaviest snowfall totals expected north of Iowa.
Voting: Good - 17 Bad - 4
Wed Mar 19, 2014
Accumulated days
19 Mar 2014 05:43 AM
The featured map yesterday compared total number of days with above average high temperature so far this year over the Midwest. Today's chart shows the total number of days again with above average high temperature to date for the past four years. The dashed line would be having every day above average and it amazing to see 2012 so close to that line! This year's total has been much smaller than the previous three years and the forecast does not hold much hope to significantly adding to it.
Voting: Good - 24 Bad - 8
Tags: 2012
19 Mar 2014 05:43 AM
The featured map yesterday compared total number of days with above average high temperature so far this year over the Midwest. Today's chart shows the total number of days again with above average high temperature to date for the past four years. The dashed line would be having every day above average and it amazing to see 2012 so close to that line! This year's total has been much smaller than the previous three years and the forecast does not hold much hope to significantly adding to it.
Voting: Good - 24 Bad - 8
Tags: 2012
Thu Mar 20, 2014
'13-'14 Winter Storm #27
20 Mar 2014 05:46 AM
We are padding the winter season stats at this point with the most recent round of snow only amounting to an inch or two over northern Iowa. Winds were strong with this storm system producing blowing snow and some difficult travel conditions. Today is the vernal equinox (start of spring), but cold weather and a few chances of snow are in the forecast after a few days in the 50s.
Voting: Good - 17 Bad - 5
Tags: winter1314
20 Mar 2014 05:46 AM
We are padding the winter season stats at this point with the most recent round of snow only amounting to an inch or two over northern Iowa. Winds were strong with this storm system producing blowing snow and some difficult travel conditions. Today is the vernal equinox (start of spring), but cold weather and a few chances of snow are in the forecast after a few days in the 50s.
Voting: Good - 17 Bad - 5
Tags: winter1314
Fri Mar 21, 2014
Accumulating the Snowfall
21 Mar 2014 04:43 AM
The featured chart presents the season accumulation of daily snowfall reports for Dubuque, Minneapolis, and Chicago (O'Hare Airport). All three sites are well above their average snowfall with Chicago more than doubling it. It is interesting to compare the season to date totals for the three sites at various points this winter. Chicago really started to pile up the snowfall after the start of the new year. Chances of more snow are in the forecast for next week, so we can add to these totals yet!
Voting: Good - 40 Bad - 11
Tags: winter1314
21 Mar 2014 04:43 AM
The featured chart presents the season accumulation of daily snowfall reports for Dubuque, Minneapolis, and Chicago (O'Hare Airport). All three sites are well above their average snowfall with Chicago more than doubling it. It is interesting to compare the season to date totals for the three sites at various points this winter. Chicago really started to pile up the snowfall after the start of the new year. Chances of more snow are in the forecast for next week, so we can add to these totals yet!
Voting: Good - 40 Bad - 11
Tags: winter1314
Mon Mar 24, 2014
Drought Concerns Remain
24 Mar 2014 05:41 AM
After the seemingly endless series of snow producing winter storms (with another one today), one might have forgotten about the drought concerns in the state. The wettest spring on record last year helped ease the 2012 drought, but dry weather crept back into the state during the summer. Outside of northeastern Iowa, all of these winter storms have not produced significant totals of precipitation and we have missed out on rainfall events. The featured chart displays trailing precipitation departures over three periods for Ames. All three periods shown are currently negative and increasing.
Voting: Good - 15 Bad - 3
24 Mar 2014 05:41 AM
After the seemingly endless series of snow producing winter storms (with another one today), one might have forgotten about the drought concerns in the state. The wettest spring on record last year helped ease the 2012 drought, but dry weather crept back into the state during the summer. Outside of northeastern Iowa, all of these winter storms have not produced significant totals of precipitation and we have missed out on rainfall events. The featured chart displays trailing precipitation departures over three periods for Ames. All three periods shown are currently negative and increasing.
Voting: Good - 15 Bad - 3
Tue Mar 25, 2014
Cold above us too
25 Mar 2014 05:37 AM
Near surface air temperatures have been a struggle recently and the same goes for the air just a few thousand feet above our head. The featured chart displays a weekly climatology of 850 hPa morning sounding temperatures from the Omaha site. The black line is a time series for this year and the dip below the 5th percentile this past weekend coincides with the cold temperatures we have experienced. With such cold air above us, any heating the sun is able to do of the surface will likely drive clouds and as we experienced yesterday, convective snow showers. Having warmer air above our heads allows near surface air to warm to higher temperatures.
Voting: Good - 16 Bad - 3
Tags: sounding
25 Mar 2014 05:37 AM
Near surface air temperatures have been a struggle recently and the same goes for the air just a few thousand feet above our head. The featured chart displays a weekly climatology of 850 hPa morning sounding temperatures from the Omaha site. The black line is a time series for this year and the dip below the 5th percentile this past weekend coincides with the cold temperatures we have experienced. With such cold air above us, any heating the sun is able to do of the surface will likely drive clouds and as we experienced yesterday, convective snow showers. Having warmer air above our heads allows near surface air to warm to higher temperatures.
Voting: Good - 16 Bad - 3
Tags: sounding
Wed Mar 26, 2014
Late for a Frozen Day
26 Mar 2014 05:37 AM
The temperature failed to reach 32 degrees on Tuesday for Ames. It is getting rather late into the spring season for this cold of high temperature to occur. The featured chart displays the dates of having a high temperature below freezing for Ames, with a fit line against the last date each spring season. The trend has been for the last frozen day of the season to come a bit earlier each year. Warmer daytime temperatures are in the forecast, so perhaps our last frozen day is behind us for the season!
Voting: Good - 21 Bad - 0
Tags: frozen
26 Mar 2014 05:37 AM
The temperature failed to reach 32 degrees on Tuesday for Ames. It is getting rather late into the spring season for this cold of high temperature to occur. The featured chart displays the dates of having a high temperature below freezing for Ames, with a fit line against the last date each spring season. The trend has been for the last frozen day of the season to come a bit earlier each year. Warmer daytime temperatures are in the forecast, so perhaps our last frozen day is behind us for the season!
Voting: Good - 21 Bad - 0
Tags: frozen
Thu Mar 27, 2014
Svr Warnings by Week
27 Mar 2014 05:38 AM
This week is Severe Weather Awareness Week in Iowa and the featured chart looks at today's topic, Severe Thunderstorm Warnings. The chart displays the weekly frequency that at least one Severe Thunderstorm Warning was issued by the NWS per year. Four states are plotted for comparison. Iowa's season starts ramping up very late March and peaks mid July. Being the furthest north of the four states compared, it takes a bit for the really warm and moist air to reach us from the Gulf of Mexico. Severe Thunderstorm Warnings are certainly not too common during the winter months in Iowa as compared with the other states.
Voting: Good - 17 Bad - 4
Tags: warnings
27 Mar 2014 05:38 AM
This week is Severe Weather Awareness Week in Iowa and the featured chart looks at today's topic, Severe Thunderstorm Warnings. The chart displays the weekly frequency that at least one Severe Thunderstorm Warning was issued by the NWS per year. Four states are plotted for comparison. Iowa's season starts ramping up very late March and peaks mid July. Being the furthest north of the four states compared, it takes a bit for the really warm and moist air to reach us from the Gulf of Mexico. Severe Thunderstorm Warnings are certainly not too common during the winter months in Iowa as compared with the other states.
Voting: Good - 17 Bad - 4
Tags: warnings
Fri Mar 28, 2014
It rained!
28 Mar 2014 05:42 AM
Something remarkable happened in Iowa on Thursday. Precipitation fell in the liquid form at temperatures well above the freezing point! The featured chart displays the times this year where the Ames Airport reported precipitation and the temperature at the time of the observation. Yesterday's event was the first time this year with precipitation at temperatures above 50. The next chance of precipitations looks to come this weekend and again, temperatures will be well above freezing. We must be dreaming!
Voting: Good - 77 Bad - 20
28 Mar 2014 05:42 AM
Something remarkable happened in Iowa on Thursday. Precipitation fell in the liquid form at temperatures well above the freezing point! The featured chart displays the times this year where the Ames Airport reported precipitation and the temperature at the time of the observation. Yesterday's event was the first time this year with precipitation at temperatures above 50. The next chance of precipitations looks to come this weekend and again, temperatures will be well above freezing. We must be dreaming!
Voting: Good - 77 Bad - 20
Mon Mar 31, 2014
Repeating 70
31 Mar 2014 05:39 AM
Strong winds helped boost temperatures to wonderfully warm levels on Sunday with Des Moines topping out over 70 degrees. The featured chart presents the frequency of having a second 70+ degree day afterwards. For the end of March, the frequencies are below 50%. The higher frequencies shown earlier in March are simply due to a limited number of events. Of course, the highest values are in July when each day is almost guaranteed to be at least 70 degrees.
Voting: Good - 25 Bad - 7
Tags: 70
31 Mar 2014 05:39 AM
Strong winds helped boost temperatures to wonderfully warm levels on Sunday with Des Moines topping out over 70 degrees. The featured chart presents the frequency of having a second 70+ degree day afterwards. For the end of March, the frequencies are below 50%. The higher frequencies shown earlier in March are simply due to a limited number of events. Of course, the highest values are in July when each day is almost guaranteed to be at least 70 degrees.
Voting: Good - 25 Bad - 7
Tags: 70