Two Snowstorms Down. The Big One Maybe Yet to Come!

Update Sunday:  I will give an updated forecast at 10:30 AM.  Waiting for the new model runs.  Very difficult forecast.  Minor snowstorm later today (definite) but a complicated, major mess tomorrow.
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The current snow event is nearly over and it appears that the forecast models did an excellent job.

Here are some of the latest snow accumulations from the National Weather Service (reported at 4:47 AM), noting that many of the reports were made before the storm was over.   My house in NE Seattle had 4 inches.   The range of snow was roughly 3 to 8 inches--very consistent with the forecasts.  And there have been some extreme snowfalls, including a reported 21 inches near Port Angeles.

Peter Benda's House in Bellevue had 8 inches

Public Information Statement 

National Weather Service Seattle WA 

447 AM PST Sat Feb 9 2019 

Location                     Amount    Time/Date 

..King County... 

2 E Renton                   8.0 in    1110 PM 02/08 

Seatac                       7.2 in    0400 AM 02/09 

Vashon Island                6.5 in    1005 PM 02/08 

Normandy Park             5.5 in    0415 AM 02/09 

Seatac                       5.5 in    0330 AM 02/09 

Kirkland                     5.0 in    1110 PM 02/08 

Bellevue                     4.5 in    1047 PM 02/08 

1 N Seattle                  3.9 in    0130 AM 02/09 

4 NNE Seattle                2.5 in    0400 AM 02/09 

..Pierce County... 

Puyallup                     8.0 in    0906 PM 02/08 

Bonney Lake                  7.3 in    1025 PM 02/08 

University Place             6.0 in    1130 PM 02/08 

Tacoma                       5.0 in    1002 PM 02/08 

..Snohomish County... 

Everett                      6.5 in    1115 PM 02/08 

Smokey Point                 5.0 in    0836 PM 02/08 

Mountlake Terrace            4.0 in    0100 AM 02/09 

..Thurston County... 

Olympia                      5.5 in    0839 PM 02/08 

The snowstorm followed the two steps I described in my previous blog.  The snow started just after noon, associated with the upward motion of an approaching upper-level trough.  Then there was a pause during the late afternoon.   Later during the evening a low center moved south along the WA coast and rotated moisture above a shallow cool, northerly flow, resulting in extended light snow.  Temperatures were on the edge, so folks next to the water had a bit less snow.

Now we have to look forward, and there is a lot of wind, snow, and cold ahead.  First, wind and cold.   Extremely strong northeasterly winds are pouring through the Fraser River gap northeast of Bellingham, with wind of 60-70 mph in places. The San Juans are being hit very hard.  Wind chills are now below zero F in some locations and will decline further.  This is dangerous stuff.

And the cold air will flood western WA today, resulting in the low temperatures tonight, plummeting to the teens in many locations of western WA.  Protect your plants, pets, and home.

Oh yes, there is the issue of more snowstorms.  The cold air will remain in placs and a series of disturbances will approach, providing the moisture.

The snow 24-h snow forecast ending 4 AM Sunday, show little over Puget Sound, but continued snow over the northern side of the Olympics.  There is LOTS of snow over southern Oregon and northern CA as the low moves southward.

During he next 24 h, a weak system will move down the coast, bringing another pulse of snow, mainly from Seattle down into southwest WA.  Lots in the Oregon Cascades (where it is really needed).  Maybe an inch or two more in Seattle.

But then we must talk about the Big Kahuna of snow, comeing in early Tuesday, with a deep low center EXACTLY where it needs to be to give us snow (see sea level pressure forecast for 4 AM Tuesday). Any Northwest meteorologists knows what this means.

The snow total forecast for the 24hr ending 4 PM Tuesday is scary, with 8-12 inches of new snow coming into Puget Sound. HUGE amounts on the Oregon Cascades...we are talking FEET of snow.

Should we worry about this?  Yes. 

Let's check another modeling system:  the ensembles of the vaunted European Center model.  Below are the forecasts of all 51 members for the accumulated precipitation at Sea-Tac Airport starting 4 PM Friday.  You see our current snowstorm (light blue colors, 3-5 inches), the Sunday event, darkening to around 5-7 inches, and then the Tuesday event, moving to the reds ( 10-16 inches).

MOST of the ensemble members are going for this...suggesting a lot of confidence in the forecast.  The average of the ensembles indicates an increase from about 4 inches from the present storm (very reasonable) to about 11 inches on Tuesday.

Keep in mind this is accumulated SNOWFALL.  Accumulation is different and usually less than total snowfall (snow can melt, be compressed, or the snow can be more dense if wet).

I am not going to suggest running out to the supermarkets, considering the bedlam that occurred before the current event.  The U-Village QFC was stripped. Some folks bought enough food for a month!  But I was really impressed how much they restocked by the next day.  Eat the stuff buried in your freezer. 😊