Past IEM Features tagged: windchill

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Coldest Wind Chill

24 Apr 2017 05:34 AM
While the cold periods this past winter season have been limited, the coldest wind chill reported for Des Moines was as cold as we have seen this past decade at about -30. Thankfully, there is no chance of having a colder temperature this spring. The top panel displays an accumulated histogram for the coldest temperature. The -30F this year is at about 70th percentile, so roughly seven out of ten years have had a colder minimum wind chill temperature.

Voting:
Good: 6
Bad: 2

Tags:   windchill  

Limited Cold Wind Chills

17 Feb 2017 05:37 AM
Very cold weather this winter has been difficult to come by as shown by the featured chart presenting the number of hours with wind chill at or below a given temperature for Des Moines. The red dots are this winter season and the blue dots are a simple average since 1973. The totals for this year are 50% of and often lower than average. The next seven days will feel more like spring than winter, so no further accumulation on this chart is expected until next weekend.

Voting:
Good: 14
Bad: 0

Tags:   windchill  

Wind Chill Advisories

15 Dec 2016 05:35 AM
A Wind Chill Advisory is in effect for much of northern Iowa this morning as cold air and brisk winds are coming to push feels like temperatures well below zero. The featured map displays the yearly frequency of Wind Chill Advisories by county in the state. The highest frequencies are shown over the flat areas of north central Iowa with Fremont County in far southwestern Iowa indicated as the lowest. Why does such a gradient exist over the state? The coldest air masses arrive in Iowa from the NW and the flat areas over north central Iowa are the windiest in the state, so this area is favored for the coldest wind chill values. Also as you go south and when winds are from the NW, these tend to be more chinook influenced, which means the air is warmer due to down-sloping from the Rocky Mountains.

Voting:
Good: 14
Bad: 1

Tags:   windchill  


Wind Chill Map

09 Dec 2016 05:34 AM
The coldest wind chills of the season thus far impacted Iowa on Thursday with wind chill values near or below zero for most of the state. How cold can the wind chill values yet? The featured map displays the 99.8th percentile coldest wind chill temperature based on long term hourly weather reports. This percentile level would approximately represent the level of the 12th coldest hour of the season. Restating, the plotted level indicates the temperature at which we'd expect to see 12 hours of wind chill at that level or colder. So for Iowa, we're in the -30 to -40 range. The map also helps equate wind chill temperatures over the country. So such weather in Iowa compares with about a wind chill of 20 above in Northern Florida :)

Voting:
Good: 17
Bad: 2

Tags:   windchill  

Wind Chill Time

10 Feb 2016 05:35 AM
The recent snow and blowing snow combined with cold air to produce sub zero degree Fahrenheit wind chill readings for the past two days. How common are such cold wind chills for the winter season? The featured chart displays the number of hours per season that the wind chill temperature is at or below a given threshold. The number of hours is expressed in units of 24 hour days for easier comprehension. The 25th and 75th percentiles are shown along with the average and maximum values. The accumulation so far this 2016 is plotted as well. Of course, we have plenty of winter season to go and the chart indicates that we have only seen about half of the time we'd expect to see such bitterly cold wind chills.

Voting:
Good: 54
Bad: 40
Abstain: 45

Tags:   windchill  


Wind Chill Alerts

18 Feb 2015 05:42 AM
The NWS has a Wind Chill Advisory issued for today as another round of very cold air arrives in the state today. The featured chart displays computed wind chill values for Ames along with periods with either a wind chill advisory or wind chill warning active. These alerts are not always issued when temperatures get very cold along with very light winds as what happened a few weeks back. High temperatures today will struggle with some locations not exceeding the single digits.

Voting:
Good: 16
Bad: 8
Abstain: 3

Tags:   windchill  

Wind Chill Warning

07 Jan 2015 05:39 AM
Air temperatures have dropped and winds have increased this morning. The combination of both have conspired to create dangerous wind chills. Many schools have cancelled classes today due to the wind chill. The NWS has issued a Wind Chill Warning for today until noon for much of Iowa. The featured chart presents the frequency of when during the day a wind chill warning is active for Story County (Ames). Rewording, when a wind chill warning is active, what is the frequency during the day that the warning was active. The afternoon hours are the least favored time, which makes sense as it will likely be the warmest portion of the day. Products like these are issued on a 3 hour increment of time, which is why there is a rapid cut off at noon.

Voting:
Good: 20
Bad: 7
Abstain: 4

Tags:   windchill  

Minimum Wind Chill by Year

30 Dec 2014 07:25 AM
Below zero wind chill readings are common over Iowa this morning. The featured chart presents the frequency of season minimum wind chill reading (top chart) and the yearly minimum (bottom chart). Every year that we have data for has seen a sub zero wind chill with at least a sub -10 degrees Fahrenheit common each year.

Voting:
Good: 9
Bad: 4
Abstain: 4

Tags:   windchill  


Wind Chill Advisories/Warnings

06 Feb 2014 06:06 AM
The entire state is under a wind chill advisory this morning with current readings in -30 to -20 range. The featured chart presents a time series of calculated wind chill values for Waterloo since 20 Dec 2013. The shaded regions are the wind chill advisories and warnings issued by the National Weather Service. There have been plenty of these events so far this winter season and only a modest break between then during the second week of January. A brief warm-up back to values closer to freezing is expected tomorrow before the next round of snow and cold pushes us back into deep freeze weather.

Voting:
Good: 35
Bad: 8
Abstain: 4

Tags:   windchill  


Comparing with 1983

09 Jan 2014 05:44 AM
The recent stretch of cold weather had a minimum wind chill of -45 degrees for Waterloo. The featured chart presents time series of wind chill using the current day equation for the ten coldest events for Waterloo. The most recent event is plotted as well for comparison. The coldest wind chill was associated with the epic Christmas Eve 1983 and is shown by the blue line. While temperatures were below -20 for two solid days this year, for the 1983 event they were close to or below -40 for three straight days! After another cold start this morning, temperatures will be improving with highs expected just above freezing on Friday for Waterloo.

Voting:
Good: 26
Bad: 1
Abstain: 2

Tags:   waterloo   windchill   1983  


Very cold wind chills

07 Jan 2014 05:44 AM
The featured map presents an IEM computed analysis of minimum calculated wind chill up until 12 AM 7 January. The lowest reading among the airport stations in Iowa was -51 from Oelwein. Most of the state bottomed out in the -35 to -45 range. Some even colder readings were found in Wisconsin, Minnesota, and North Dakota. A few isolated locations were able to reach -60! Temperatures will be on the rebound today with highs above freezing expected by later in the week!

Voting:
Good: 27
Bad: 4
Abstain: 5

Tags:   2014   windchill  


Wind Chill Frequencies

06 Jan 2014 05:39 AM
Much of the Midwest is in the firm grasp of winter this Monday morning with extreme cold and gusty winds making for life threatening conditions. Wind chill readings this morning are some of the coldest in many years. The featured chart presents the percentage of winter seasons that experience a given threshold wind chill reading for at least one hour that winter. Almost every year gets down to -20 with about half reaching -35. The extreme temperatures reached today will be in the 10% or lower frequencies, which means this is once in a decade or two weather.

Voting:
Good: 61
Bad: 5
Abstain: 3

Tags:   windchill  


Below 0 Windchills

20 Feb 2013 05:41 AM
Tuesday was a brisk reminder of the winter season we are still in with wind chill values below zero for most of the state. The featured chart displays the daily frequency of having at least one wind chill reading below zero. Three selected sites are shown for comparison. The frequencies peak out around 60% for most of January and the first few weeks of February. We are on the downward slope of this chart as we creep closer to springtime.

Voting:
Good: 32
Bad: 6

Tags:   windchill  


Wind Chill Hours

25 Jan 2013 05:41 AM
The featured map presents an analysis of the average number of hours per year that the wind chill reading is below zero. The total number of hours is presented in units of 24 hour day periods for easier comprehension. While there are some local poor data effects, the north to south pattern is clear with the nation's ice box around 50 days and the south under 1 day. The gradient over Iowa is fairly strong with northern Iowa near 30 days and southern Iowa around 10. The past week has seen the coldest wind chills over north central Iowa, which makes the preferred region in the state for the most frequent sub zero wind chills.

Voting:
Good: 67
Bad: 13

Tags:   windchill  


Plenty of cold for all

04 Feb 2011 05:52 AM
The featured map presents an IEM analysis of the lowest wind chill temperature reported so far this month. In the wake of our most recent blizzard storm system, very cold air has frequented a good portion of the country pushing wind chill values below zero for places like Texas. Some of the coldest wind chills ever recorded were present for some locations in Oklahoma and Kansas. Values below -50 F were observed as well. The good news is that our immediate future has a slight warm up with temperatures close to freezing!

Voting:
Good: 28
Bad: 5

Tags:   windchill  


click image for better view

The wind and the cold

21 Jan 2011 07:04 AM
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  


wind chill calculated using the current equation

Frequency of cold wind chills

12 Jan 2011 05:52 AM
A bitter north west wind is blowing this morning and with temperatures in the single digits, wind chills are well into the negative range. The featured chart presents the number of hours per winter season that wind chills values below -20F were reported at the Des Moines and Sioux Falls airport. During every year, except one, Sioux Falls has had more hours below -20 than Des Moines. The chart does show that these bitter cold temperatures have been less common in the past ten years than the previous 30. The brutal winters of 1977 and 1978 show up prominently on the chart.

Voting:
Good: 15
Bad: 4

Tags:   windchill  


2008 data up until 3 Feb 2009

Sub Zero Wind Chills

03 Feb 2009 06:13 AM
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