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Sub zero readings possible Friday morning

Less than two weeks ago, on Nov. 2, the Twin Cities saw a high temperature of 56 degrees. But that sun-splashed Sunday seems so distant.

We have short memories.  What has Mother Nature done for us lately?

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Temperature plot for MSP for November.

Notice the relatively tight temperature profile between the maximum and minimum temperatures, a signal of cloud cover and a breeze in the overnight hours.

I don't see any change in this trend for the next five days.

In one regard to the early winter cold and snow, take a look at the exceptional snowfall that has occurred this week in Michigan's Upper Peninsula. Ironwood reported 34 inches.

This lake effect snowfall occurs when colder air travels over the relatively warmer waters of the Great Lakes picking up moisture and depositing  the snowfall across the landscape.

A longer  fetch of winds across the open waters of the lake helps to enhance the snowfall accumulation. There is more  time for the clouds to gather moisture to deposit the snowflakes inland.

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Simplified graphic of lake effect snowfall process.

This morning's  snowfall map shows the extent of snow cover in Minnesota, Wisconsin and  Upper Michigan.

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Image:Midwest Regional Climate Center.

As skies clear tonight and winds drop off, we set up the opportunity for sub-zero overnight low temperatures, particularly where the snow cover is significant.

I'm thinking the area from Little Falls to Milan has the best chance of seeing daybreak temperatures on Friday -- slightly below zero.

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National Weather Service Forecast for minimum temperatures on Friday morning.

The record-low temperature for St. Cloud on Nov. 14 is 8 below zero, set in 1940.  I think the record will stand.

I'm still tracking the chance for accumulating snow on Saturday for southern Minnesota.  For this minor snowfall event, it appears the gradient for measurable snow will be quiet tight across central Minnesota including the Twin Cities.

A snowfall of one to three inches looks most likely from Marshall, through Owatonna to about Rochester.

The National Weather Service Office in Sioux Falls offers this graphical forecast heading into the weekend.

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The National Oceanic and Atmospheric Administration's Weather Prediction Center is holding with the best chances for snow south of the Twin Cities.

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Probability of snowfall of 2 inches or greater for Saturday.

If you are looking ahead to outdoor activities, on Saturday temperatures are expected to be mostly in the 20s statewide and winds are forecast to be rather light.

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Winds in knots for noon CST on Saturday. Image:National Weather Service.

A re-enforcing shot of cold air arrives Monday and will keep afternoon high temperatures about 15 to 20 degrees below normal.

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Forecast maximum temperatures for Tuesday, November 18.