Updraft® - Minnesota Weather News

You be the forecaster: How much snow Monday?

A lot of weather geeks read this space. Thanks for that! Let's try something different today.

I'll post more updates about the inbound snow system through the weekend, but I'd like to make this post available as an opportunity for you arm chair and professional meteorologists out there to place your forecast bets on the eventual storm track and snowfall totals for Monday's system.

Here's a brief read on my latest thinking based on today's model runs so far.

First the latest read from the Twin Cities NWS.

1107 msp3

OVERALL...CONFIDENCE IS HIGH ON ACCUMULATING SNOW ACROSS FAR SOUTHERN MN SUNDAY NIGHT WITH 1 TO 2 INCHES OF ACCUMULATION BY DAYBREAK MONDAY. THE SNOW WILL CONTINUE ACROSS SOUTHERN MN ON MONDAY WHILE SPREADING INTO ADJOINING AREAS OF WI. POPS WERE RAISED IN THESE AREAS TO LIKELY/CATEGORICAL. CONFIDENCE IS ALSO INCREASING ON THE TOTAL SNOWFALL ACCUMULATION EXCEEDING 6 INCHES ALONG AND SOUTH OF THE I-90 CORRIDOR. HOW FAR NORTH THE ACCUMULATING SNOW REACHES IS IN QUESTION DUE TO THE DEPTH OF THE LOW LEVEL DRY AIR. AT THIS POINT...ITS LOOKING LIKE A WILLMAR...SOUTHERN TWIN CITIES TO EAU CLAIRE LINE IS WHERE AN INCH OR LESS REACHES. A WINTER STORM WATCH MAY NEED TO BE ISSUED IN THE NEXT 24 HOURS.

Here's the set up as we head through the weekend. Saturday's arctic breeze sets the stage by pumping cold air south. By Sunday morning, the main low pressure wave is riding the edge of the arctic dome southeast into Montana, spreading an advancing snow shield into the Dakotas.

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NOAA

Most models track the low into eastern Wyoming by Sunday night, then eastward on a track south of Minnesota toward Chicago Monday.

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NOAA

The big question for Minnesota? How far south, or north will the low pressure center (and associated snow) shield track?

NOAA's current GFS model will be replaced by a newer version in December. Here's what the GFS run lays out for snowfall as of Friday morning's 12z (6 am) run.

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Projected snowfall totals from the 12z GFS run. NOAA via wxcaster.com

As you can see the 12z GFS has shifted the heavy snow band a bit north, and now puts significant snow into (especially the southern) metro Monday.

Updated: The latest Euro runs agree with the northward shift and now crank out .93" liquid for the metro Monday.

1107 e2
Norwegian Meteorological Institute

As usual I'll hold off on any concrete snowfall predictions until about 24 hours before the snow flies. In my experience that's the window of time where the accuracy of models and the need to know snowfall totals for planning purposes optimally meet.

At this point the most likely scenario to me seems to be to lay out the heaviest snow band between the metro and the I-90 corridor, with the Twin Cities riding the northern edge. Any track shift north would bring heavy snow into the metro. Any shift south and metro snowfall totals drop significantly.

What do you think? What is the eventual storm track and where will snowfall totals wind up?

Discuss!