Wednesday Snow Storm

I just looked at the latest model runs and it seems clear that we are going to have a major (but not a record) snowstorm, one that is NOT followed by major warming and heavy rain.  No Slushmageddon, just Snowmageddon.  Near all modeling systems are taking the low south of us--thus the uncertainty is considerably less than a day or two ago.  (But to be fair, there is a chance that the solutions we have are wrong!)  With the low going south, the cold air can stay in place...in fact, the cold air will be reinforced with flow moving southward out of British Columbia.   But a southward trajectory also lessens the precipitation amounts in the central and northern portions of the state...so NW WA may get very little.
Since the forecast is so critically dependent on the exact position of the low, we need to watch that today.   There is still a chance this could end up as a wet event....snow turning to rain, particularly over the southwestern portion of WA.

And there is something else...ANOTHER pulse of snow will occur on Thursday.

Cutting to the chase, Seattle may well get 6+ inches of snow during the next two days.  SW Washington could get more.  The mountains, particularly the central Cascades southward could get feet--like 3-4 feet.  In short, one of the biggest events we have had in years.

This has been a hard forecast for the models because there are two airstreams battling it out...one from the north and one from the south.  Small displacements of the low (order of a few hundred miles) makes all the difference.  Consider that the system has developed and moved over thousands of miles...this is not an easy thing to do.

There has been some hype about this event...it is NOT going to be as bad as December 1996.  I remember that well.  We had two snowstorm the last week in December and I had 21.5 inches on the ground at my house.  Then it got very warm and windy and heavy rain rapidly melted the snow.  Just a disaster, with collapsed roofs and slope failures.

Heavy snow followed by warm rain collapsed Edmonds boat shelters

You want to see some weather maps!  You bet.

Tonight and tomorrow a weak disturbance is moving through with lots of snow showers. (see radar image below).  Substantial snow shadowing in the lee (west) of the Olympics.  Some folks out of the shadow will get a few (2-4) inches.  Child's play compared to what will happen on Wednesday morning.

On Wednesday AM a low center, with an associated warm front will approach our region, and by 10 AM (42h forecast chart below) will be reaching the coast, while cool air remains in place over most of western WA.  Another weaker low will follow on Thursday AM.  Two snow events. Clearly, we are just on the edge of the interface between the cool and warm air, which makes the forecast much harder.

Here are the predicted snowfall maps for 24h ending 4 PM Tuesday (first one) and 4 PM Wednesday (second one).   During the next 24h, there will be light snow over the western lowlands (less in the central Sound) and lots of snow in the mountains.  For the subsequent 24 h, there are huge amounts in the Oregon and southern Washington Cascades and heavy amounts (8-12 inches) over the western lowlands.  Eastern Washington and Oregon also get hit hard.

Here are blow up views for 24 hr snowfall ending 4 PM Tuesday, Wednesday, and Thursday

Bellingham gets cheated!   And did I mention strong winds coming out of the Fraser River Valley and hitting NW Washington?  Here is what is forecast for 1 PM on Wednesday:

Sometimes so much happens at once that is hard to keep up with it...Wednesday will be like that.  This event will do wonders for the NW snowpack...particularly in Oregon where they have really been hurting.  And we haven't talked about the extraordinary precipitation totals to the south of us, where some places will be getting 10-20 inches of rain (or its equivalent in snow)  (see graphic):

As shown by this water vapor chart....this is the result of the famed pineapple express, with moisture streaming out of the tropics and subtropics towards the West Coast.

I am exhausted thinking about all this weather action.  Anyway, lets watch this carefully tomorrow....looks solid...but no forecast is certain and if this prediction goes south, it won't be the first time.  The  southern part of the Washington could see snow turning to rain.   Keep in mind EVERYTHNG is dependent on the location of the low pressure...if it moves farther north than our models suggest we could see much more rain in the mix.

PS:  No luck finding my lost dog Leah tonight...but she appears to be running around in the area around 220th and 64th Ave W in Mountlake Terrace, near the Moose Casino.  Let me know if you see her...info on the right...thanks...