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.

Features for Jan 2018

Mon Jan 01, 2018
2017 Temperature Range
01 Jan 2018 05:59 AM
The featured map displays the difference between the warmest and coldest temperature based on hourly high-resolution analysis produced by the Real-Time Mesoscale Analysis (RTMA). The coldest air of the entire year arrived last evening and helped to make this map even more extreme. Most of Iowa is shown in the 110 to 120 degree range. Even more extreme values are found just to our north and west with a few pixels over 140 degrees! There are many interesting features on the map with the moderating effects of the Great Lakes clearly evident and the decreased variability in temperature as you get further away from land.
Voting: Good - 9 Bad - 0

Tags:   2017   rtma  
Tue Jan 02, 2018
Decreasing Range
02 Jan 2018 05:31 AM
Yesterday's featured map displayed the range between the coldest low and warmest high temperature for 2017 over the CONUS. Today's featured chart shows the long term trend of this temperature range by year for Des Moines. Besides the yearly bars representing the temperature ranges, the chart also has long term and recent averages and the trailing 30 year average (yellow highlighted line). That trailing average is rather interesting as it shows a downward trend in range over the past 30 years or so. 2017 bucked this trend somewhat coming in well above the three averages shown.
Voting: Good - 6 Bad - 1

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Wed Jan 03, 2018
About the Decreasing Range
03 Jan 2018 05:32 AM
This week's features have been looking at the yearly range between the warmest high and coldest low. Yesterday's feature showed a downward trend in range, meaning the difference between the warmest high and coldest low was decreasing. Today's featured chart looks more closely at this decrease. The top panel shows the yearly max temperature, the middle panel shows the yearly min, and the bottom panel shows the yearly difference between these two. An overall average is overlain for each series and a trailing 30 year average is presented as well. The trailing 30 year average shows the warmest highs decreasing and coldest lows increasing (both on average), so that would explain the decreasing range.
Voting: Good - 9 Bad - 1

Tags:   range  
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Thu Jan 04, 2018
Almost 72 Hours Straight below 0
04 Jan 2018 05:33 AM
Seasonally mild temperatures have been a struggle recently with numerous hours having below zero Fahrenheit values. In fact, many locations in the state recently completed a significant stretch of consecutive hours below zero. The featured chart shows the streak for the Des Moines Airport, whose streak of 2 days and 18 hours finished in the top ten longest since 1936 based on unofficial hourly archives maintained by the IEM.
Voting: Good - 7 Bad - 1

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Fri Jan 05, 2018
Rare Recent Record Low
05 Jan 2018 05:34 AM
Des Moines started off the new year by establishing a new daily record minimum low temperature of -19 degrees. This broke the previous record of -18 set way back in 1887! The featured chart looks at the year that the present day daily record is either set or currently tied. The four sections present the year of the daily record and a simple decade frequency. For the current decade, setting record cold lows and cold highs have been rare. This decade has the lowest totals for both values. There are a number of interesting features of the chart including how the 1930s stand out for record warm highs and lows.
Voting: Good - 12 Bad - 1

Tags:   climate  
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Mon Jan 08, 2018
Coldest Eight Days for Lows
08 Jan 2018 05:33 AM
Temperatures on Sunday were downright balmy with high temperatures above freezing and lows above zero! For places like Ames, this was the first day with a low above zero since 29 December making for eight straight days. The featured chart looks at the coldest stretch of eight days based on average low over that period. The horizontal bars denote the period of days and the color denotes the value for that period. The bottom panel displays a frequency for the individual day of the year participating in this period. So having this happen during early January isn't that exceptional, but one wonders if a colder period of eight days could still happen later this winter season? The frequencies would indicate that chances are still good for that to happen.
Voting: Good - 6 Bad - 0

Tags:   lows  
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Tue Jan 09, 2018
Doing Well for January Highs
09 Jan 2018 05:34 AM
High temperatures on Monday were an awesome relief from the bitter cold to start off the new year. Highs were well above freezing and even into the 40s for parts of Iowa. This is doing very well for January as average highs for the month are generally below freezing for the state as shown by the featured map depicting an analysis of NCEI climatology for the month. We'll have two more very nice days before winter returns in full force on Wednesday into Thursday.
Voting: Good - 8 Bad - 0

Tags:   jan  
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Wed Jan 10, 2018
Winter Storm Warning Counts
10 Jan 2018 05:34 AM
The featured map displays the number of winter storm warning events issued by NWS Offices since 1 October 2017. Please note that these events are not necessarily equal to the number of storms. Anyway, of interest is that places like Honolulu, Hawaii and Jacksonville, Florida have issued more winter storm warnings than local offices here in Iowa except Davenport. Iowa's total of Winter Storm Warnings will increase with the impending storm arriving tonight and into Thursday.
Voting: Good - 6 Bad - 0

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Thu Jan 11, 2018
Flash Freeze
11 Jan 2018 05:41 AM
The term "Flash Freeze" appears to be relevant today as precipitation is falling over top a very strong arctic front. The featured map shows the combination of near surface air temperatures, road surface temperatures, and RADAR. The strong front can be seen with temperatures in the 40s quickly dropping into the 20s along with precipitation happening on both sides of this boundary. This creates a very dangerous situation as wet roads are quickly exposed to temperatures well below freezing. After the freeze, snow will fall and strong winds are expected to create near blizzard conditions. Going to be a tough travel day today.
Voting: Good - 18 Bad - 0
Fri Jan 12, 2018
'17-'18 Winter Storm #6
12 Jan 2018 07:54 AM
Our brief respite from cold winter weather ended on Thursday as a winter storm brought rain, freezing rain, sleet and snow to the state. The amount of snow produced was under what was anticipated, but the cold temperatures and dangerous wind chills did materialize for today. The featured map presents a smooth analysis of reports received. There were fewer than normal amount of reports made for this event as generally low totals and cold temperatures likely were discouraging for snowfall reports to be made. More snow and cold is in the forecast as winter rolls on for Iowa.
Voting: Good - 9 Bad - 2

Tags:   winter1718  
Mon Jan 15, 2018
'17-'18 Winter Storm #7
15 Jan 2018 08:09 AM
Our continuing series of fluffy and light producing snow storms continued Sunday evening with most of the state picking up an inch or more. Amounts approaching six inches were reported over far Northeastern Iowa. Strong winds after the snow produced blowing snow and near whiteout conditions over northern Iowa. We are again left with very cold temperatures and dangerous wind chills after the passing snow storm. The official snowfall report for Des Moines was again below three inches, continuing the record stretch for the site to nearly 750 days.
Voting: Good - 9 Bad - 1

Tags:   winter1718  
Tue Jan 16, 2018
Sun Dogs
16 Jan 2018 05:34 AM
If you were outside yesterday afternoon braving the cold conditions, you likely noticed a very bright "Sun Dogs" display. These are the two bright spots horizontally on either side of the sun and are caused by light refraction through vertically oriented / falling ice crystals. These are common during cold and blowing snow situations. The featured image is from the KCRG-TV webcam in Iowa City Monday afternoon showing the right-hand (to our perspective) sun dog.
Voting: Good - 4 Bad - 3

Tags:   sundogs   webcam  
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Wed Jan 17, 2018
Dips Below Zero
17 Jan 2018 05:34 AM
The past three weeks have seen plenty of bouts with below zero weather. The featured time series is of hourly temperatures from the Ames Airport since late last year. The blue stripe represent the climatology range between the daily high and low temperature. The chart shows seven events during this period with the temperature below zero. The good news for those that don't like this very cold weather is that warmer temperatures are in the immediate near term forecast with highs even well above freezing later this week!
Voting: Good - 8 Bad - 1

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Thu Jan 18, 2018
Fairbanks Recently Warmer
18 Jan 2018 05:41 AM
The featured chart compares daily high and low temperatures between Des Moines, IA and Fairbanks, Alaska since 1 December 2017. The past four days have seen warmer temperatures there than here. During this time of year, such a difference isn't all that rare, but the perception that Alaska should always be colder than we are! Due to large scale atmospheric flow patterns, having very cold weather in Iowa is often juxtaposed with very warm weather in Alaska. Our weather is in the process of warming up and any thoughts of moving to Alaska for warmer temperatures will diminish!
Voting: Good - 7 Bad - 0

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Features for Jan 2018