A Colder Period Ahead with A Chance of Scattered Light Snow over the Western Lowlands

 The last month has been considerably colder than normal over the region, with eastern Washington being particularly frigid.    The coldest air this season will arrive on Sunday.

To put you in the proper mood,  take a look at a plot of the difference in our daily temperatures from normal over the past month (see below).   Eastern Washington has been frigid, with temperatures 6-12 F below normal, while western Washington has been 2-6F below normal.


This contrast will get even more dramatic during the coming days.  

It is interesting to note that electric energy demand increases with the cold temperatures and that hydro is providing most of the energy (see recent Bonneville statistics below).   Renewables (solar, wind) provide very, very little.   It is important that when we need the most energy (when it is very hot and very cold) wind energy is generally minimal in our region..   One reason I strongly support nuclear energy development.


Our region will stay moderately cold and decidedly dry through Saturday.

But on Sunday afternoon through Monday morning, cold air and high pressure will push southward from British Columbia, as illustrated by the surface chart at 4 AM Monday. (below). The lines indicated sea level pressure and the colors show the temperature at around 2500 ft above the surface.   Blue, purple, brown and white colors are cold enough to snow.

Northwest Washington and eastern Washington are the coldest in our state at that time.   Insane cold over the BC interior and east of the Rockies.


Here are the forecast temperatures at SeaTac Airport for the next week based on the NOAA/National Weather Service NBM prediction (which uses many models and data sources).  Monday and Tuesday would have highs only reaching the mid to upper 30s and lows in the 20s.


What about Eastern Washington?   MUCH colder.  At Pasco, for example, the temperatures will fall into the teens at night, and single digits will be widespread.


What about snow?   

This coming push of cold air will not have a lot of moisture with it (sorry kids).

The first chance will be on Sunday as the cold air pushes southward.   Here is the forecast for total snowfall through Sunday at 4PM.  Some snow in the mountains and eastern WA, but only scattered snow in western Washington.  Bellingham, the San Juans, and the northeast side of the Olympics are the best bets.


The snowfall from the lower-resolution European Center model (for the 24h ending 4 AM Monday) suggests the potential for a band of convergence zone snow over Puget Sound....but nothing dramatic.  Some models had previously predicted a second snow event, but most are backing away from it.

In any case, I will keep a close watch on the snow potential.   And as we get closer, I will have more powerful tools available.


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