HIGH IMPACT WINTER STORM

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

A major winter storm is set to get underway tonight, with the potential to produce snowfall of a foot or more. Travel is expected to become hazardous and difficult Saturday. The Weather Prediction Center expects major impacts locally, which are outlined below.

As I expected, the NWS has now expanded winter storm warnings for my entire area for the long duration event, which gets underway tonight and wraps up early Sunday. By then, winds of up to 30 mph should lead to areas of blowing snow, particularly in outlying areas.

The epicenter of the storm will be centered directly over my region, but significant impacts will be found over most of the central Midwest, meaning holiday travelers Saturday all around the region will experience tough sledding.

The water vapor loop of the GOES satellite shows the energy coming out of the Rockies where it scoops up ample moisture and deposits locally as snow.

Some models indicate QPF water equivalent greater than 1.50 inches. At a straight 10:1 ratio, that's 15 inches of snow potential. The HRRR, a high resolution CAM (convective allowing model) actually depicts 1.58 inches near the Quad Cities.

The NWS model and official snowfall forecast by them has a general range of 10–14 inches.

Odds of 8 inches or more are 100 percent north of I-80.

Between HWY 20 and I-80, (north of the 850mb circulation), odds are 80 percent or greater of 12 inches or more. 86 percent in Cedar Rapids....that is strong!

The snow starts late evening in the west and spreads east after midnight. Peak snow rates should be from roughly noon to midnight Saturday. Here's a timeline.

For the most part, model guidance this morning has changed little, if anything, amounts have gone up, especially on the high-res CAMS such as the HRRR and 3K NAM. As always, here is the latest raw model output, individual solutions that are not hard forecasts. However, they figure into the official NWS forecast, which I showed above. An experimental product known as the NBM V5 is a blend of 30 model solutions and ensembles. It shows this.

THE EURO

The 3k NAM

The HRRR

The 12K NAM

The GFS, interestingly enough, is much lower on overall precipitation totals and the lowest for snowfall projections. It's an outlier, but if correct, it would bring the lowest snow totals. Even so, it's still generous, with a range of 9–13 inches.

About all I can say, with less than 12 hours to the start of the storm, is that this is as high a confidence forecast as one can ask for when it comes to consistency in model guidance. All the players are on the field, now all they have to do is perform. Here's hoping nobody drops the ball. More to come later this afternoon, and don't forget the Facebook live briefing at 8:00pm with meteorologist Nick Stewart. You will not find anything more in depth than what we'll drop on you! Roll weather...TS