Warm Wisconsin Thanksgiving to give way to Snow?

Nov 24, 2012
The prospects of a winter storm early next week has diminished for the upper Midwest. Most computer models are now advertising a zonal atmospheric flow that will inhibit a strong low pressure system to evolve. The prospects of snow should increase as we move into December.

November 20 Blog Update

The 00z ECMWF run has come in and as expected, the major snow storm is now longer there. It appears the 500 mb flow has become more progressive and has lost its amplified solution. The GFS model is somewhat saying the same tune with no storm forecast. Colder air is still looking likely across the upper Midwest, so that appears to unfold than a storm at this point. Things can still change this far out, so Stay Tuned!

November 19 Blog Update

A nice ridge of high pressure will usher in warm, possibly record high temperatures for much of the upper Midwest. High temperatures may even reach in the 60's across southern Wisconsin on Thanksgiving. These balmy conditions will be short lived, as a strong cold front will move through the region that will bring colder air.

Of a interest is a second push of artic air that may invade the upper Midwest next week. Some computer models are suggesting a strong baroclinic zone setting up across the Midwest. This pattern is represented by cold air lurking across the Rockies and warm air over the Great Plains. This contrast in temperatures can bring the prospects of a strong storm system to develop and ride up the baroclinic zone. The long range ECMWF and GFS models show this potential. The AO and NAO are trending negative as well, which supports this possibility. The GEM (Canadian Model) is not on board yet with this solution but it bears watching.

*Please note When a pattern change is expected in the long term, models have a hard time painting an accurate picture of what will happen. You may get a storm on one model run and then it's gone the next run.

What is more certain is the prospects of colder air moving south out of Canada next week. The CPC (Climate Prediction Center) is forecasting below normal temperatures for most of the Plains and upper Midwest. Regarding the storm, I'll post any further developments the next few days. Let the model watching begin!

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