Shot of winter: Snow and colder temperatures

Santa Claus may have been wearing a disguise this year. That may have actually been Old Man Winter who finally paid a visit to Minnesota.

Better late than never?

The weather maps finally look (and feel) more like winter this weekend. Our weekend weather fare? Snow and colder temperatures.  With temperatures below freezing, any snow that falls has a much higher impact than previous slop storms with pavement temperatures above freezing. It's a good reminder that it's more about impact, than inches in winter in Minnesota. A coating of flurries at 10 degrees can turn an entire city into a skating rink, but 2" of melting snow at 36 degrees has little impact.

With temperatures below freezing, expect the impact of slick roads Saturday no matter how many inches fall in your back yard.

Weather headlines

• Winter storm warnings include southwest Minnesota and the Duluth area.

• Winter weather advisories up for the Twin Cities and central Minnesota.

• Snow expands late tonight and Saturday across Minnesota

Big Picture

Strong low pressure rides through the southern Plains this weekend. The system is unusually loaded with moisture, what meteorologists call "high precipitable water content." Heavy, to flooding rains fall in the south central U.S.. Minnesota rides the northern end of the moisture. It's (finally) cold enough here for snow.

Heaviest snows northwest of metro

Snow bands spread north and east across Minnesota into Saturday.

The heaviest snow axis sets up from southwest Minnesota towns like Marshall and Canby through Willmar, St. Cloud toward Duluth. That puts the heavier snows northwest of the Twin Cities metro area. NOAA's Rapid Refresh model (RAP) seems to have a good handle on the spatial layout of precip across Minnesota. A quick shot of snow sailing through the metro in the hours surrounding midnight, with the steadier heavier snow bands favoring western and central Minnesota toward Duluth.

Widespread impacts this time

This system spreads snow across a wide region. With so many of you travelling home from holiday gatherings, here's a tour of the Upper Midwest this weekend.

First the view from Sioux Falls.

The heaviest snow zone for this storm? Likely eastern South Dakota and southwest Minnesota. Up to a foot could fall in South Dakota along I-90 west of Sioux Falls. Snowfall totals as high as 4" to 8+" edge into southwest Minnesota.

The view from the La Crosse NWS. An icy mix is likely along the I-90 corridor as the rain-snow line waves overhead.

Duluth and central Minnesota.

And finally the Twin Cities. I'm not ready yet to buy into the higher end snowfall totals depicted in the maps below. But again impact is most important. Any snow will grease up the roads pretty fast with temps below freezing.

Overall I favor a metro snow range between 1" and 4" by Saturday afternoon. Lighter totals seem to favor the southeast metro, with the best chance of 2" to 4" in the northwest metro. At least on paper. This has been a crazy winter for snowfall so far. When in doubt, under-forecasting snow totals has been the wise path.

Bottom line: Expect snow of varying intensity across the southern 2/3 of Minnesota into Saturday. With temps below freezing slick roads will be an issue.

2015 closes colder

Temperatures over the next week finally look and feel more like the December we are used to at this latitude. Another snow chance arrives Monday and Tuesday, but some model trends are steering that storm south of Minnesota.