Thanksgiving Weather: The Evolution of a Forecast

Thanksgiving is one week from today.  It’s so close you can smell the turkey and stuffing.  You’re already seeing the holiday commercials advertising their 4:00AM opening on the day after Thanksgiving.  There are probably radio stations switching to full-time holiday music this weekend.  (And let’s be honest, it’s Christmas music with Adam Sandler’s Hanukkah song mixed in every six hours.)  The joy, anger, cheer, and stress will begin raining down next week, but will the sky unleash precipitation to hamper your travel?  That’s what we’re here to discuss.

I’ve saved the Thanksgiving forecast from the GFS model for the past six major model runs.  (The GFS is actually run four times per day, but the 00z and 12z runs are the major solutions most often referred to in forecasts.)  Specifically, the forecast solution is valid for 7PM EST/4PM PST on Thanksgiving day.  The precipitation is that accumulated over the 6-hour period prior to the solution’s time.  After the jump (i.e., click “read more” below), you’ll see the six images beginning with the 00z run on Tuesday, 11/17.  Keep in mind we are still a week away from Thanksgiving and much can change between now and then.  This should only be considered a preliminary look at the forecast.

240-hour Thanksgiving forecast. Click for larger image.

228-hour Thanksgiving forecast. Click for larger image.

216-hour Thanksgiving forecast. Click for larger image.

204-hour Thanksgiving forecast. Click for larger image.

192-hour Thanksgiving forecast. Click for larger image.

180-hour Thanksgiving forecast. Click for larger image.

Looking through these images, there is one consistent theme: warm in the west, cold in the east.  However, the timing and strength of this temperature shift varies, which isn’t all that surprising when you consider how far into the future we’re looking within each model run.

As far as precipitation is concerned, there is consistently an area of precipitation in the Northwest as well as the Great Lakes and Northeast.  It’s not worth considering precipitation totals at this point, although it does appear to be relatively light.  If the colder solutions verified, lake effect snows would certainly be possible in the Great Lakes, which would mark the first widespread lake effect snows for the region this year.

If anything, this shows you how much the forecast can change from run to run.  In some cases, the low pressure center in the east is along the coast, in other cases it’s in southern Ontario.  (Sometimes it’s not there at all.)  The one thing we might be able to gather from this is temperature.  Cooler in the east and warmer in the west has been the theme since Paul Yeager looked 384 hours out last week.  That’s the most we can take from the forecast right now.  We’ll see what, if anything, changes this weekend.

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