Large Part of Iowa Now Under Winter Storm Warning For Sunday

[UPDATE: Saturday morning] The winter storm we've been warning you about for three days already is beginning to descend on Iowa. Today will be a nice day, but the change will come late tonight and throughout the day Sunday.

The National Weather Service has issued a Winter Storm Warning for all the counties shaded in pink below. The purple counties are under a Winter Weather Advisory, where less snow is expected.

The warning goes into effect at 3 a.m. Sunday (11/25) and continues through midnight. A 21-hour Winter Storm Warning. The precipitation will begin as rain before changing over to snow. Heavy snow is expected with total accumulations of four to eight inches, with isolated higher amounts likely. Add winds gusting to 35 miles-per-hour and Sunday is not going to be a fun one, with travel expected to be very hazardous.

CBS 2 Chief Meteorologist Terry Swails and the National Weather Service both believe the EURO will be the weather model that is closest to correct on this storm. It shows snow amounts varying from two to seven inches in Johnson County, with as much as ten in Washington County.

The GFS still expects it to be a much wider spread heavy snow event with as much as 16 inches in a small area in central Iowa, but ten-inches-plus very common. Stay tuned.

[UPDATE: Friday morning] The National Weather Service has now issued a Winter Storm Watch for most of Nebraska, northern Kansas, and the southern half of Iowa (including Des Moines, Cedar Rapids, Iowa City, and the Quad Cities) as a winter storm continues to come together. Parts of northern Missouri and extreme western Illinois are also included.

The Watch takes effect late Saturday and continues until Sunday evening. At this time, the National Weather Service says,

4 to 8 inches of heavy, wet snow are possible, especially along and west of the Mississippi River. A north wind gusting over 30 mph could also create hazardous travel
conditions, with blowing and drifting snow, and very low
visibility at times. Downed tree limbs and power lines are also possible. There is still uncertainty on the track and strength of this storm system and more adjustments to the forecast are likely.

One thing now looks a virtual certainty. A major winter storm is going to hit beginning Saturday night and will continue through the day on Sunday. If you have travel plans during that time period, please move them up. A snowstorm, especially with the type of winds that could accompany it, is nothing to mess with. Please stay safe and share this information with friends and loved ones with travel plans for the end of the holiday weekend.

Here's a look at the current expectations for snow:

[UPDATE: Thanksgiving morning] The likelihood of a major winter storm for the last part of the holiday weekend is increasing. CBS 2 Chief Meteorologist Terry Swails reports that both weather models are now indicating a significant snowfall event. The first, the Global Forecast System (GFS), indicates anywhere from four to six inches across the majority of the eastern third of Iowa. Unfortunately, the one that appears more likely forecasts much more.

The ECMWF (European Centre for Medium-Range Weather Forecasts) model is the one that shows a massive snowfall event for a large part of Iowa, Wisconsin, and northern Illinois. It shows a foot of snow in many places.

Here's what Terry says about the below forecast model:

The EURO solution has been the most consistent in terms of track. It's also the most aggressiveness in terms of snow production. I favored its solution yesterday and I see no reason to back away from it. Obviously there will be tweaks in the next 48 hours but overall I think it has the right idea.

Stay tuned.

[Original Story] Mother Nature is going to be kind to us for the beginning of the Thanksgiving holiday weekend, but the back end could be a whole different story. Terry Swails, Chief Meteorologist at our partner CBS 2, says "we have a solid trend for what looks to be a potent winter storm." Great. Just great.

Terry reports a low is expected to track to near Quincy, Illinois and, if it does, that could spell big trouble for Iowa and Wisconsin. It would mean rain, snow, and strong winds. I hate to use the dreaded word blizzard, but it definitely bears watching.

Terry's Global Forecast System (GFS) model shows a huge snowstorm from southwest Iowa all the way through the center of Wisconsin. That model expects central Iowa to get the worst of the storm. Here in eastern Iowa, we could still see several inches of snow but most of the precipitation would fall as rain, before changing over late in the storm. The other model isn't so kind to snow-haters in the corridor.

Here's what the ECMWF (European Centre for Medium-Range Weather Forecasts) shows. Ten inches-plus of snow is pretty common, in a narrow band.

This big storm is expected to affect our area Sunday through Sunday night, so keep up with the latest forecast over the next several days.

Oh, and after the storm rolls through look for a very cold week next week with temperatures in all of Iowa below normal. According to Terry, "this final round of cold will see to it that November 2018 is one of the coldest on record."

Remember when I told you three months ago that the Farmers' Almanac and Old Farmer's Almanac both thought it was going to be a wet winter in Iowa? Oh, wait, winter STARTS one month from today. Great. Just great.