- Jan 11, 2018

BACK TO REALITY IN A BIG WAY....

Well, we finally had a 40 degree day Wednesday, the first since December 19th. That ended a 20 day stretch of cold that was pretty darn intense. For much of the Midwest it was the coldest stretch of weather since February 2013. The low of 24 below here in Cedar Rapids was just 5 degrees from our coldest all-time temperature of 29 below set in 2009.

The worst of the cold was endured during the period December 25 to January 7 when temperature departures averaged 18 degrees below normal over that 13 day stretch.

It's interesting that the onset of the cold coincides with the official start of winter, December 21st. Since then we've seen plenty of Arctic air and in most areas several inches of snow. Below you can see what NOAA predicted for winter temperatures. I'm on the record for saying I've always expected this winter to be far colder than what NOAA was indicating with below normal temperatures. I thought snow would be close to normal but for that to happen we are going to have to make up for a slow start and plenty of lost time.

Today will be a fun day if you like changeable weather. A stout Arctic front will wing its way across eastern Iowa in the morning. My area can expect dramatically colder conditions and temperature falls of up to 30 degrees in 12 hours time. In this meteogram for Cedar Rapids you can see the temperature drop from 42 at 6am to 13 at 6pm. Winds over 30 mph will plunge wind chills to 10 below by mid afternoon!

Following the passage of the Arctic front will come showers that quickly transition to snow. The best forcing for accumulations will occur in my western counties, especially in Iowa. At the time of this post (late Wednesday night) the newest models were showing an eastward shift on the system that could bring an inch or two of snow roughly northwest of a line that runs from McGregor to Cedar Rapids. There are some complex mesoscale processes going on that make this a low confidence snowfall forecast. By morning we should have a much better idea of how snow bands and amounts will lay out. The GFS Wednesday night had this for snowfall totals through Thursday evening.

Here's the regional perspective.

Behind the storm comes more Arctic air, the worst of which holds off until Monday and Tuesday. Even so, highs over the weekend are likely to remain deep in the teens, a good 10-15 degrees below normal. Here's the 5 day temperature departures for the period Friday through Tuesday. Back in the deep freeze.

By the way, there is another system to watch for snow Sunday night. Amounts look light generally 1-2" around my area at this time. Here you can see a surface low cutting across N. Illinois Sunday night dumping a fluffy high ratio snow.

It's behind this clipper that high winds and bitter cold air arrives Monday and Tuesday. The GFS has highs in my northern counties remaining below zero Tuesday.