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.


Comments

Post a Comment

Popular posts from this blog

The Time of Year You Can See the Air Move

Image
  Most of the time, you can not see the air move.   You can feel it, but the complex, turbulent motions are invisible to you, except when it interacts with leaves and branches on trees and plants. But for a few weeks of the year, the sky is full of small, cotton-like tuffs that like a natural MRI machine reveals the complex three-dimensional motions of the atmosphere.   Cottonwood season.  And we right in the middle of it.   Being cottonwood aware is of particular value this year.  It reveals the active dispersion and movement of air that makes the outdoors essentially COVID safe, and thus should be of some comfort for those nervous about transmission outside. Cottonwood seeds are embedded in small cotton-like fibers.   A million seeds weigh about 3 pounds.  Yes, each seed and tuff weights about .000003 pounds.   And that fact, plus the cottonwood tuff, means that these seeds fall VERY, VERY, VERY slowly.   So slowly that they are excellent markers for the three-dimensional flow of the
Read more

Why so little lightning in the Pacific Northwest? And a very nice weekend ahead.

Image
During the past 24-hours, there have been a few lightning strokes over the region (see below) but nothing to write home about (see below). It turns out that the Pacific Northwest and the remainder of the West Coast have some of the lowest frequencies of thunderstorms in the entire country (see below). But why?    My podcast provides the answer. And I also give the weekend forecast....and I think most will like what I have to say. To listen to my podcast, use the link below or access it through your favorite podcast service. Some major podcast servers:     Like the podcast? Support on Patreon 
Read more

Strong Atmosphere River Heads into British Columbia and Southeast Alaska

Image
While the Northwest has been drier than normal, it has been drenching wet a few hundred miles to the north. An unusually strong atmospheric river ....a long current of moisture stretching southward to the subtropics...has been in place for days, bringing large amounts of water vapor to Alaska.   And the atmospheric river will be in place for several more days, slowly moving southward. To illustrate, the scale and beauty of the atmospheric river, here is a water vapor satellite image for 11 AM today. The lighter areas have more water vapor.  You can see the current of moisture extending from near Hawaii into central BC.  This current is the result of low pressure over the Gulf of Alaska and high pressure offshore of California.   A forecast of total water vapor content in the atmosphere for 11 PM tonight shows a healthy atmospheric river (white and blue colors indicate the higher amounts of moisture). As this atmospheric river slams into the mountainous West Coast, the air is forced to
Read more