The featured map presents an IEM produced analysis of snowfall reports from the epic blizzard. Snow totals over a foot stretched from Oklahoma to Chicago to the east coast. The heaviest totals in Iowa were around 18 inches. The presented map does have one caveat that some of the snowfall from the first storm over the weekend was included in the snowfall reports used to make this map. The departure of the storm has left us bitterly cold air and wind chills well below zero.

Voting:
Good = 26
Bad = 5

Tags:   winter1011   blizzard  

With the entire state under a blizzard warning during portions of Saturday and Sunday, one may wonder if the entire state experienced blizzard conditions. The term blizzard is typically applied to a period of at least three hours where visibilities are less than 1/4 mile due to snow or blowing snow along with wind speeds at or above 35 mph. People typically do not stand outside during strong winter storms, so it is hard for them to meet the three hour requirement and only report an instantaneous blizzard. Automated weather equipment struggles at low visibilities... The featured chart shows a comparison between reported three hour visibilities and wind speeds. Both plots contain two sets of data. The 'best wind' dataset includes the variable combination when winds were the strongest. The 'best vis' contains the observations when visibilities were the lowest. The x-axis is shown in log format, so to visually see smaller values. The left hand chart uses max/min values over the three hours, while the right hand chart uses simple averages (helping out the wind criteria). Even using the more lenient method, only ~20% of the sites in Iowa hit blizzard criteria in this qualitative form. For those that were outside, they probably considered the weather blizzard like.

Update: NWS Directive has the blizzard warning criteria as "Sustained wind or frequent gusts greater than or equal to 35mph accompanied by falling and/or blowing snow, frequently reducing visibility to less than 1/4 mile for three hours or more." (but no definition of what "frequently" means)

Voting:
Good = 39
Bad = 10

Tags:   winter1011   blizzard   nws  

A powerful winter storm system is winding up this Saturday evening over Iowa with the entire state now under a blizzard warning as shown by the featured map. The counties shown in pink also have local civil emergencies warning motorists to stay home as no help will be available if they get stuck. Winds have been extreme with gusts over western Iowa topping 60 mph. In the wake of this storm system, very cold air is set to arrive on Sunday and Monday with highs hopefully in the single digits.

Voting:
Good = 45
Bad = 6

Tags:   winter1011   blizzard  

The featured chart looks back at the recent blizzard experience for the state and compares IEM estimates of State Patrol road travel advisories and closures with statewide estimates of mean wind speed and NEXRAD reflectivity coverage. The chart shows that the peak in snowfall coverage came before the maximum wind intensities. You can also see a very clear relationship between the improvement of road condition with the decrease in wind speed on Wednesday evening (Dec 9th).

Voting:
Good = 53
Bad = 14

Tags:   blizzard   road   nexrad  

An epic winter storm has most of Iowa shut down this Wednesday morning with snowfall amounts approaching a foot and a half in areas. The big story now is the blowing snow thanks to strong winds blowing over 30 mph sustained. These winds are due to a tremendous pressure gradient over the state. The featured image shows the pressure drop yesterday for the Des Moines ASOS at 34 millibar in a 24 hour period. This rapid change, perhaps unprecedented, in pressure will help keep winds strong today and roads in Iowa impassable.

Voting:
Good = 86
Bad = 8

Tags:   blizzard   bomb   pressure  

Today's feature is provided by BUFKIT Warehouse proprietor Chris Karstens.
The featured plot shows the NAM forecast of hourly qpf (in.) and mean mixed layer wind speeds (mph) for Slater, IA, initialized 6pm CST Sunday. A good shot of snow looks to be on tap this morning, with winds picking up later in the afternoon and evening, gusting near 40 mph, making for blizzard conditions. The National Weather Service has issued blizzard warnings for the expected impact of this morning and this past weekend's snow blowing around leading to whiteout conditions.

Voting:
Good = 23
Bad = 8

Tags:   bufkit   blizzard