Temperature tops 40 in Twin Cities; Saturday’s precipitation could be mixed bag

The thermometer overachieved in southern Minnesota this afternoon. A push of milder air on southwest winds to 25 mph combined with a couple hours of sunshine to boost the mercury to 48 F at Fairmont and 41 F at Minneapolis – St. Paul International Airport.

Lack of snow cover and frozen soil in Iowa allowed the mild south winds to usher in quiet a warmup. Ames, Iowa topped out at 50 F this afternoon. Note on the map below the chilly readings in the teens in northwest Minnesota.

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Click on map for larger view. Valid at 3 p.m. CST. Temperatures in red. Wind barbs in knots. Source:NOAA

The milder temperatures melted considerable snow on the side streets. Some refreezing later tonight will result in slick spots. Be cautious when traveling outside the Metro late tonight.

Perhaps the easy part is predicting moisture late Friday and Saturday for much of central and southern Minnesota and Wisconsin. While the storm track looks favorable for snow in the Twin Cities, relatively mild surface and low-level temperatures will result in the potential for mixed rain, snow and freezing rain.

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NOAA’s precipitation, liquid content, for Friday night and Saturday, issued on Wednesday afternoon.

Based on an estimate of one to eight, for liquid to snow and expecting some of the moisture to fall as mixed rain and snow, I come up with about 4 inches of snow on Saturday somewhere in central Minnesota. We are still a long way from noon Saturday. There will be several computer runs to help define the potential snowfall.

The National Weather Service forecast discussion from Chanhassen this afternoon has this to say about the Saturday’s precipitation:

SNOWFALL TOTALS FOR SATURDAY ARE CURRENTLY IN THE 3- TO 4-INCH RANGE FROM THE REDWOOD FALLS/MONTEVIDEO AREAS ON NORTHEAST THROUGH ST CLOUD AND MORA AND THEN EAST ACROSS HIGHWAY 8 IN WEST CENTRAL WI. TWO TO 3 INCHES INDICATED FOR THE TWIN CITIES.

One of the forecast tools is the vertical profile of the atmosphere. The GFS model shows temperatures slightly above 0 degrees Celsius in the Twin Cities at the surface on Saturday morning. If this forecast holds, we could experience a mixture of rain and snow and an air temperature in the lower 30s.

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GFS sounding valid at 6 a.m. CST Saturday. If you click on image, reduce to 75% to view temperatures in Celsius. Temperature lines run diagonal.

Source:NOAA and Twisterdata.com

As the surface low tracks from Iowa into southern Wisconsin on Saturday it will carry the bulk of the precipitation east of Minnesota Saturday night.

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GFS valid at noon CST. Precipitation from 6 a.m. to noon. Surface pressure pattern and wind with low pressure center in Iowa. Source:NOAA/College of Dupage.

Paul will be back on Thursday to track this weathermaker. A blast of arctic air is not expected to follow in the wake of Saturday’s precipitation.

Craig Edwards

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