A Pleasant No-Drama Thanksgiving Weekend: But A Big Surprise

After a stormy previous week, we can look forward to a relatively dry and temperate Thanksgiving holiday, without the drama of significant storms.  

Of interest, it will be MUCH warmer in western Washington than in the Columbia Basin, which has moved into the typical mid-winter cloudy/cool pattern.

To illustrate, the weather.com forecast for Seattle predicts consistent temperatures, with highs in the mid to upper forties, no frost, and minimal chances of precipitation.    Lots of opportunities to burn off some of the excessive calories from too much eating.

But consider the forecast for Kennewick in the Columbia Basin (below).  Every day, it will drop well below freezing at night, with highs in the upper 40s on most days.

The best day of the weekend should be Sunday when a big upper ridge of high pressure will develop over the eastern Pacific (see 500 hPa map--about 18,000 ft-- at 7AM Sunday).  Expect plenty of sun on Sunday afternoon.

But it will get even better than this.  A HUGE ridge will develop on Monday and Tuesday (the map on Tuesday at 7 PM shown below).  Even more sun.  Totally dry.

The Big Surprise

La Nina is dying.  Below is a plot of the sea surface temperature anomaly (difference from normal) for the central tropical Pacific.   Last year, there was an El Nino with sea surface temperatures above normal (orange colors).  Then a weak La Nina started in August with temperatures dropping very modestly below normal.

But shockingly, during the past weeks, La Nina collapsed with temperatures near normal.

The recent summary of sea surface temperature forecasts (below) keeps a very weak La Nina for a few months before it collapses.    The real world sea surface temperatures suggest that the models are too slow.

These forecasts suggest a near-normal snowpack this winter and plenty of storminess.