The Upcoming Arctic Push Into Washington State: In Living Color!

 Why travel to the northern climes when Arctic air is coming to you?  

High pressure and very cold air are now moving into British Columbia.  

It would like to reach us, but the mountains--the Rockies and Cascades--are initially blocking it.

But like like a marginal football team, there are gaps in our defense.   Literally gaps in our terrain.

And the cold offense is about to make a successful end run to score a frosty goal.

Let me show you....

The situation this morning shows cold temperatures (purple and brown colors) in the Canadian Arctic.  An intense pressure change is at the interface between warm air to the southwst and cold air in the interior.

Zooming in temperatures and winds in Washington State, at 10 AM today the state was divided by Cascades (just like our politics!).   Cold in the east (purple colors) and warmer in the west (green colors).


By tonight at 10 PM, much colder air moves into southern BC (while shades), and cooler air pushes through the Fraser River valley north of BC and into NW Washington.


Sunday morning at 7 AM, colder air is pushing south into the Okanagon River Valley in north central Washington and modifed arctic air is surging in the Northwest Washington, pushed by strong northeasterly winds escaping the Fraser River Valley,


The process continues through Sunday at 10 PM and if you look carefully you will see northerly winds pushing into Puget Sound.   Cold air is really moving southward into eastern Washington.


What about snow tonight and tomorrow?

Precipitation is already moving into the region, but it is falling as rain over the lowlands.

The snow total forecast through 4 AM from the NOAA HRRR model shows mountain snow, but little over the lowlands with two excptions. (see below).  The first is around Bellingham, where cold air from the Fraser Valley will support light snow, and the second is on the northest side of the Olympics, where the Fraser Valley flow is forced upwards.

 Why travel to the northern climes when Arctic air is coming to you The Upcoming Arctic Push Into Washington State: In Living Color!

For the period through 4 AM Monday, there is more NW Washington snow and a band of light snow over Seattle.   That is probably associated with a weak convergence zone;  it totals less than 1 inch in its core.  Southwest WA gets some light snow as well.  


Later Sunday and Monday should be a dry, but cold period.

The next possibility for snow is late Tuesday, but at this point it appears that northwest WA is most threatened.   More details in a future blow.








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