A wild day of weather across the Nation
HARRISONBURG, Va. (WHSV) - A very interesting day of weather across the country for Wednesday, December 15th, 2021.
SNOW AND SEVERE
Another round of severe weather expected for the Plains and the Upper Midwest and what’s most interesting, and odd- is that on the morning of December 15th, there was still some snow on the ground for areas outlined in the greatest risk of severe weather! That’s something you don’t see, well ever. Keep in mind it warmed up substantially through the day and some melted- but not all.
Now this all started as an extremely powerful cold front that was strengthening through the day. A deep area of low pressure that was intensifying was contributing to the extreme wind forecast from the Rockies, to the Plains and Great Lakes region. Peak wind gusts from several stations were as high as 100mph!
Yes, that’s correct, a massive dust storm today started in Colorado, and moved into Kansas and Nebraska. Many of these area are in an incredible drought right now. The powerful wind and dry air behind the severe threat drove a dust storm that created a “wall of dust”, prompted dust storm warnings and was visible on satellite imagery.
EXTREME FIRE THREAT
Because of the dry conditions, and extreme wind, there were many areas under an extreme fire threat. Unfortunately several fires did start and spread rapidly. Satellite is picking up on fires in the Texas and Oklahoma panhandles and Kansas.
Not only was there a severe weather threat from the Plains to the Great Lakes, but storm movement was exceptionally high. Several tornado warnings that were issued had storm movement of 70-80mph, that’s how fast the storm is moving! Usually a fast storm is 50-55mph.
A movement over 60mph is extremely unusual and incredibly fast. At one point the NWS issued a tornado warning for a storm that was moving as fast as 100mph. That’s movement, not wind in a storm. With the extremely fast forward motion of a storm, this enhances wind damage.
A December Derecho
A derecho is a very long lived complex of storms that is exceptionally severe. It can be showers or storms but long lived with extremely high wind. You may remember the Ohio Valley and Mid-Atlantic derecho of 2012. Derecho criteria is:
Damaging winds with a path of at least 250 miles
Wind gusts of at least 58mph across most of the path and usually along the leading edge. So yes, this was a derecho on December 15th, 2021.
Several National Weather Service offices have been surveying tornado damage from December 15th. Right now between four states, more than 50 tornadoes have been confirmed from December 15th.
AND THEN THERE WAS SNOW
Because this is a cold front- there’s cold air once it crosses. For some that had severe weather in the afternoon, well it might be snowing now.
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