Days with Low At or Above Freezing
02 Jan 2017 05:13 AM
For the recently finished calendar year of 2016, the Des Moines weather station had the most number of days with low temperature at or above 32 F. The featured chart presents the accumulated total of days for 2016, average, and envelop between the least and greatest accumulation. The 2016 total of 275 days eclipses the previously largest total set just last year of 273 days.
Voting: Good - 11 Bad - 0

Tags:   2016  
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Winter Low Ceilings
03 Jan 2017 06:01 AM
Monday was a rather dreary day with low clouds, freezing rain, and then rain. Winter is the season for such low clouds as shown by the featured chart. The chart depicts a histogram of cloud ceilings as estimated by the Ames Airport weather station. The darker reds represent the more conditions. There is a clear signal in the lowest levels during the coldest half of the year. Low clouds are more difficult to persist during the warmer season as solar inputs generally are able to warm the ground to mix the lower atmosphere.
Voting: Good - 11 Bad - 0

Tags:   ceilings  
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Bottoming out in January
04 Jan 2017 07:00 AM
With cold air back in the state for Tuesday and the rest of this week, it is good to provide some optimism for warmer temperatures. The featured chart displays three climatologies for daily temperature for Ames. Two of them are smoothed for the standard climate period of 30 years and the bars represent the simple arithmetic average based on period of record data. It is interesting that while the smoothed climatology show average temperatures rising by the middle of this month, the period of record data continues in the downward direction.
Voting: Good - 9 Bad - 0

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Just a dusting
05 Jan 2017 08:02 AM
A fast moving system brought just a dusting of snow for most of southern Iowa overnight. Totals approached an inch near the Missouri border. As an administrative note, the tallied IEM 'Winter Storms' of the season have an arbitrary requirement of two inches of snow or significant impacts. So we won't be counting this as a season storm!
Voting: Good - 9 Bad - 0

Tags:   winter1617  

Temps since 1 December
06 Jan 2017 05:35 AM
For the past two days, it has been a struggle to get temperatures out of the single digits and along with a brisk wind, it does not feel pleasant outside. The featured chart displays a time series of air temperature reports from Ames since 1 December of last year. The shaded area represents the range between the climatological daily high and low temperature. Our current cold weather ends a respite since our last cold weather back in mid December. Temperatures are expected to reach 30 degrees by Monday, so something to look forward to!
Voting: Good - 8 Bad - 1

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Few Fairbanks Days Warmer
09 Jan 2017 05:32 AM
When it gets cold in Iowa, it seems common to compare our temperatures with a location that is always assumed to be very cold, like Alaska. The large scale weather patterns are such that when it gets very cold in Iowa, it is often not relatively cold in Alaska. The featured chart displays the daily differences in high and low temperature for Ames with Fairbanks, AK. Just a few days during our recent few weeks has Fairbanks been warmer, while most days are significantly colder with an average difference around 35 degrees! So if somebody suggests that you move to Alaska to experience warmer weather, you will want to make the move a very brief one or find a warmer part of the state than Fairbanks.
Voting: Good - 9 Bad - 0

Tags:   alaska  
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Snow Cover Differences
10 Jan 2017 05:32 AM
The presence of snow cover has been quite inequitable this winter season. The featured map displays a smoothed estimate of the number of days with at least one inch depth snow cover reported. The gradient depicted over the state is rather large with over 32 days shown near Decorah to only four to eight over most of southwestern Iowa. The presence of snow cover makes a big difference in daily temperatures and soil temperatures. Some of the snow cover will be melted today with above freezing temperatures expected over most of the state.
Voting: Good - 10 Bad - 2

10 January Travel Troubles
11 Jan 2017 05:31 AM
Travel was very difficult early Tuesday morning for many Iowans due to a layer of ice that formed on roadways. The setup for this icing event was rather tricky as shown by the featured chart. The chart depicts Jefferson RWIS road pavement and air temperatures, solar radiation observations from the Jefferson KCCI-TV SchoolNet and DOT/DPS Road Condition Reports. The yellow bar represents the time period that a road segment near this road sensor's location was reported to be partially covered with ice. The temperature time series show the interesting combination of having air and dew point temperatures above freezing with road temperatures below freezing. This combination along with falling rain left to the rain freezing on the road surface. The rain also likely helped to wash off much of the pre-treatment done on Monday. The cold front then trucked through after 10 AM dropping the air temperature below freezing as well, but the clouds broke up during the afternoon hours and pavement temps warmed back above freezing even with falling air temps. Many locations further north did not have pavement temps warm back above freezing and icy conditions remain a problem there.
Voting: Good - 6 Bad - 2

Tags:   rwis   icing  

Large Temperature Difference
12 Jan 2017 05:34 AM
The air temperature difference over the Midwestern US on Wednesday was rather extreme with record highs in Missouri and values below zero over North Dakota. The featured chart displays automated station reports over the region for Wednesday. The bottom panel shows the spread between the coolest and warmest reading by hour. Temperature differences maxed out at over 90 degrees!
Voting: Good - 9 Bad - 0

Since Last Ice Storm Warning
13 Jan 2017 05:33 AM
A well advertised winter storm is expected to bring significant accumulations of ice to the southern plains and maybe into Iowa. Numerous NWS Offices to our south have issued Ice Storm Warnings in advance of the event. This type of warning is not all that frequent as the conditions for significant icing have to be just right. The featured map displays the number of days since the last issued (prior to the current event) Ice Storm Warning by NWS Office. For many folks under the current warning, it has been a good number of years since a previous warning.
Voting: Good - 14 Bad - 0

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Icy State
16 Jan 2017 07:16 AM
A significant winter storm has brought plenty of freezing rain to the state. The featured map displays Monday morning road condition reports with most of the state partially or completely covered with ice. NE Iowa is currently in travel not advised category. Conditions will be dicey today with more rain entering the state and temperatures continuing to hover around freezing. The good news is that the rest of this week looks much warmer, which should help to melt off the ice accumulating now.
Voting: Good - 11 Bad - 0

'16-'17 Winter Storm #7
17 Jan 2017 05:33 AM
The most significant ice storm to hit Iowa in a number of years is thankfully mostly over. The featured map is an attempted analysis of freezing rain accumulation reports provided by the NWS Local Storm Reports. Please note that areas in northern Iowa are heavily estimated and smoothed due to lack of reports. Hopefully more reports come in on Tuesday and an updated map can be generated. Temperatures are expected to warm this week, which should help to melt most of this recent ice.
Voting: Good - 10 Bad - 0

Tags:   winter1617  

Time Yet for Snow
18 Jan 2017 05:03 AM
Snowfall totals so far this season have been paltry over southern Iowa. Although we are now half way through meteorological winter, the bulk of our snowfall typically has yet to come. The featured chart displays the before vs after 17 January snowfall totals each winter season for Des Moines. The total this year is about four inches and there have been a handful of previous years around that total as well. The averages for each period are plotted and it shows that the last half of winter is typically the snowiest.
Voting: Good - 13 Bad - 0

Tags:   snow  
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Warmest Since Christmas
19 Jan 2017 05:34 AM
Temperatures warmed nicely on Wednesday for much of Iowa. The featured map displays the last calendar date with as warm a high temperature that was experienced on 18 Jan 2017. For locations like Ames and Des Moines, you have to go back to Christmas Day 2016 for as warm a high temperature. For Sioux City, you have to go even further back to 4 December 2016! All the locations with the warmest temperature since Christmas are colored red on the map.
Voting: Good - 2 Bad - 1