WINTER STORM GAINING STEAM

LIVE WINTER STORM BRIEFING FRIDAY AT 8:00PM

Friday evening at 8:00, myself and meteorologist Nick Stewart will do a special Facebook live briefing on the holiday weekend storm which will be knocking on the door We'll have the latest warnings, watches, and snowfall trends. Join us Friday night for an in depth perspective on the storm you won't find anywhere else. TS

HAPPY THANKSGIVING!

After a wild day Wednesday that saw a wind gust of 64 mph in Cedar Rapids, our weather will slowly but surely improve the next 48 hours. Winds, while strong Thanksgiving, will be more in the range of 15-25 mph. Skies should turn mostly sunny and the trip to grandmas looks uneventful with highs in the range of 32 north to 37 south. Similar temperatures are expected Friday, with an increase in clouds during the afternoon.

THE STORM

By now, most of you have heard that a snow system is on track to impact the region late Friday night though Saturday night. I spent much time discussing the event on a Facebook live Wednesday night. As a result, this post is abbreviated and confined to the latest trends and snowfall output for Saturday. For more in depth information on the storm, see my 1-hour briefing in its entirety at https://www.facebook.com/tswails Additionally, I will have an updated snowfall forecast Thanksgiving afternoon. I also plan another LIVE Facebook briefing at 8:00pm Friday night ahead of the storm. More if needed.

Meantime, models remain in relatively good agreement Wednesday night regarding snow potential and confidence continues to grow that a significant snowfall will impact my area beginning late Friday night. Snow does not conclude until late Saturday night and by the time it ends, accumulations well over 6 inches are a real possibility. The ensembles of the EURO, comprised of an average of 50 members, suggests this for potential accumulations at a 10:1 ratio.

The EURO ensembles

The GFS ensemble is a bit lower but consistent in regard to where the heaviest amounts might occur.

The deterministic run of the EURO and GFS takes into account snowfall ratios higher than 10:1. This adds several inches to the totals, especially on the EURO, which has higher total liquid precipitation. Here's what it indicates. Definitely the worst case scenario for the highest snow amounts.

The GFS, noticeably lower.

The 12K NAM, hot off the press.

It's still too early to say with certainty where the heaviest snow ends up falling and determine a range. However, based on where we are 48 hours ahead of the event I would say that the majority of my area should see 5–10 inches, with the potential for a narrowband somewhere that could max out greater than 10 inches. This has the potential to be a high impact storm.

As mentioned, I will have more on the latest trends later Thanksgiving afternoon.

As it stands now (still subject to change), the Weather Prediction Center indicates an 80 percent or greater chance of snowfall meeting warning criteria. A Winter Storm Warning for the Quad Cities is typically issued for significant and dangerous winter weather, including at least 6 inches of snow in 12 hours, 8 inches in 24 hours. I fully expect a winter storm watch to be issued by the NWS that could include most of my area sometime Thursday.

Breaking news: After posting this, I went to the bathroom to brush my teeth and go to bed. My phone went off, alerting me to the fact my the majority of my area had been placed under a winter storm watch for 6 or more inches of snow starting late Friday night through Saturday night. Surrounding counties are sure to be added. Hats off to the NWS for pulling the trigger.

The Winter Storm Severity Index through the day Saturday currently shows moderate impacts locally. It's possible based on trends Wednesday night, that the heavier snow with greater impacts could be shifted further south to include my southern counties as well.

Anyway, stay with me for fresh updates later Thursday. It will be a big day for firming up trends, forecasts, and winter storm watches.

By the way, some notable snow storms have hit the area the weekend following Thanksgiving. One was in 1985 and a more recent one was 2018. Steve Gottschalk, the weather guru from Lowden, put together this report on the post Thanksgiving storm of 2018.

On Nov. 25, 2018, a strong low pressure system tracked across Kansas, Missouri and central Illinois. In its wake, it brought heavy snow and blizzard conditions to N.E. Missouri into E.C. Iowa and N. Illinois.

Along with the heavy snow, lightning and thunder and wind gusts from 30 to 50 mph were present throughout the storm.  Snowfall rates of 1" to 2" an hour were observed. The snowfall totals ranged from 0.0" in northern Cedar and Linn Counties to 15.0" in Mahaska County. The heavier totals between 8.0" to 12.0" were common in a line from Sigourney to the Quad Cities. Some of the higher totals were:

Moline Airport - 13.8"

Parkview - 13.0"

Sigourney - 13.0"

Clinton - 12.1"

Henry and Whiteside Counties, Illinois -12.0"

Davenport (NWS) - 11.9"

New Boston, Illinois - 10.0"Washington - 9.0"

Donnellson - 8.0"

Here's a look at some of the final snowfall totals....

Here in Cedar County at my weather station in Lowden, I recorded 6.0" of which 3.0" fell in 2 hours between 2 p.m. and 4 p.m. Just 1.5 miles west of town there was only 2.0" and another mile even further west there was barely 1.0". The town of Clarence 7 miles to the west of here had a few flurries and Stanwood another 5 miles, west had nothing. The town of Bennett, 9 miles to the south of Lowden received 14.0", while Calamus just to the east, picked up 11.00". During the storm, I had northerly winds gusting to 40 mph, along with lightning and thunder and zero visibilities. A very impressive system for those who saw and felt it!

Another perspective showing the sharp cut-off to the snow on the NW flank.

In all of my 64 years of weather observing, I have never seen such a dramatic cutoff in the snowfall. In summer, yes, with thunderstorms, but not with snowstorms. Is this a new trend?

That's all for now, see you later today. Have a fantastic Thanksgiving and roll weather...TS