Snow winds down through Friday; subzero air locks in next week

Our massive, lollygagging, dayslong storm is finally beginning to wind down across Minnesota. The heaviest snow bands and bursts are over. Scattered, occasional snow showers will linger through Friday in many areas.

Check out the National Oceanic and Atmospheric Administration’s NAM 3 km model, which shows the center of the low-pressure storm swirling over the Twin Cities through noon Friday:

Overall, expect another 1 to 3 inches for many areas through Saturday. The North Shore could add another 5 inches in some areas.

Incredible snowfall totals

More than 2 feet of snow was reported at multiple locations along the North Shore and northeast Minnesota. As of this post, Finland still leads the Golden Snow Shovel contest with 29 inches of heavy wet snowfall up on the hills above Lake Superior.

It’s interesting to note that snowfall totals are lower along the lakeshore where it was warm enough for mixed precipitation. But as the air rose up the hill, adiabatic cooling changed it to heavy snowfall.

Air masses cool about 5 degrees for every 1,000 feet of elevation gain. That wrings out even more snow on the ridge tops.

This sprawling weather system dumped even heavier snowfall in South Dakota’s Black Hills, where 3 to 4 feet fell!

You can check the latest snowfall totals across our region here.

Excellent forecast model performance

The forecast models for this week’s storm performed very well. First, they have a week’s lead time on a major system. Also, they pretty much nailed the thermal profile suggesting a rainy mix in the Twin Cities with the heaviest snowfall across northern Minnesota and the North Shore.

Check out this clip from my Updraft post last Thursday, December 8.

Eastern Minnesota may see a light wintry mix Saturday. Then a bigger, slower storm looks like it has the potential to dump some heavy snowfall across central and northern Minnesota.

Right now the early forecast models suggest the freezing (rain-snow) zone could set up near the Twin Cities.

Stay tuned.

The forecast models also nailed the two-part nature of this system.

A week’s lead time on a major winter storm with an accurate outcome? Overall, you can’t ask for much better model performance and lead time for Minnesota weather consumers. This storm was a big weather forecast success story.

Subzero air ahead next week

Next week brings a bitterly cold air mass into Minnesota. It will likely be our first prolonged subzero stretch of the cold season.

The European and American models suggest teens below zero next week, with the upstream air mass capable of 20s to 30 below zero in southern Canada and northwestern Minnesota.

Stay tuned.