More Snow is Ahead for the Pacific Northwest

 Special Message:

  Could be a major aurora tonight (Sunday) for our region.   Lots of clouds right now, but there should be some clearing in a few hours in western WA.

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The snow forecast went quite well this morning over western Washington, with portions of central Puget Sound picking up the predicted 1-2 inches (see observed snowfall noted this morning by the CoCoRahs cooperative network).  


This was a very difficult forecast, with marginal temperatures.   The kind of forecast we could not have done 15-20 years ago.

But there is a downside to this increased forecast skill, a negative impact that directly affected me this morning (see below).  I was REALLY looking forward to a pastry and cup of coffee before I went to work at the UW.   No luck.

but there should be some clearing in a few hours in western WA More Snow is Ahead for the Pacific Northwest

Another snow event for western Washington looms.....and another difficult forecast.

Why difficult?  Because major weather prediction models were in disagreement about a crucial weather feature, and we are close to the edge regarding temperatures over western Washington and Oregon.

There have been subtle differences in the location of a low-pressure trough along the Washington/Oregon Coast that influences precipitation, and thus snow, over western Washington.

The European Center was going for more snow over central Puget Sound, but now the latest U.S. GFS model simulation (initialized 6-hr later) has joined in the snowy fun.

Below are the forecast accumulated snowfall totals for both models through 4 PM Tuesday.

The European Center shows over 3 inches for Seattle and Portland, except right near the water.
but there should be some clearing in a few hours in western WA More Snow is Ahead for the Pacific Northwest

The updated U.S. GFS model is similar but with more snow over the lowlands.  The mountains get hammered in both.


When will the snow arrive? Tuesday morning.

The European Center is quite confident snow is in our future.  Below are the cumulative snowfall totals in Seattle from the large and excellent EC ensemble system of many forecasts.  Each line represents a different forecast run.  Virtually every run turns blue (snow).  Purple is even more.

The average of the ensemble forecasts for Seattle snow is shown below (light blue bars)--around 5 inches of snowfall is predicted.  The solid line is a single higher-resolution prediction....even more.

but there should be some clearing in a few hours in western WA More Snow is Ahead for the Pacific Northwest

Tomorrow I will provide more details based on higher-resolution local simulations.

One final note:  I ask that no one tells the Grand Central Bakery about the forecast.  The reasons are obvious.

but there should be some clearing in a few hours in western WA More Snow is Ahead for the Pacific Northwest

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