November 03, 2017

Light Snow Reaches the Lowlands of Western Washington

Snow revved up in the mountains yesterday, but this morning the snow level fell to near sea level over several locations of western Washington.

About an inch at 1300 ft in Bellevue (picture courtesy of Peter Benda)

The upper-level flow pattern was a classic for western Washington snow with high pressure offshore and a sharp trough of low pressure reaching the Northwest coast (see upper level map at 5 AM).    This pattern brings both upward motion (which produces precipitation and clouds) and helps push cold air into the region.

If this was a month or two later, we would have been worrying about a major lowland snow event.

Cooler air and higher pressure first moved into British Columbia yesterday, and as a result cool winds started blowing in the Fraser River Valley northeast of Bellingham, where northeasterly winds revved up yesterday (see below).  Winds gusted to 39 knots (45 mph) there, and temperatures plummeted from the upper 40s to 31F.  And yes, it is snowing there.

The is cool, but not super cold---still very early in the fall/winter season, of course.  The cool air pushed south overnight, with northerly flow ascending  the northern Olympics, enhancing snow in places like Port Angeles and Sequim (see map at 6 AM).  No rain shadow for these weather-spoiled folks.
Snowy Sequim

The freezing level (the height where the temperature falls to freezing) dropped all day yesterday, and the latest observations at Sea-Tac airport suggest it is at about 1300 ft (950 hPa pressure)--see the time-height cross section below (red lines are temperature, x-axis is time, y-axis is height in pressure).

Heavy precipitation showers can push the freezing and snow levels (the lowest level of snow) down to near sea level, and we do have unstable air and showers over the region (see radar at 7:04 AM)

The model forecasts had suggested this snow interlude.  Here is the 24-h snow amount ending 5 PM today from last nigh's run.  Not bad!  And the mountains are going to be hit hard today.  Note the substantial upslope snow on the north side of the Olympics.

Today the lowland precipitation will quickly end as the area of showers moves through.  So Seattle and other lowland mayors can rest easy.  Furthermore, road surfaces are relatively warm. 

But the snow fun is not over.    Another upper trough and associated low moves in Saturday night and Sunday, with some significant lowland snow, particularly south of Seattle (see forecast below).  Olympia gets hit hard. Lots of uncertainty with keep tuned.

This is a La Nina winter and this situation is classic for a La Nina year.  The Cascades will have a good start to a winter base for skiing and other snow fun.  I mean several feet above 5000 ft.
NWS Snow Reports

Public Information Statement
National Weather Service Seattle WA
1056 AM PDT Fri Nov 3 2017

..Updated Snowfall Reports...

Location                     Amount    Time/Date       Elevation (ft.)      


..Clallam County...
3 SW Port Angeles            10.0 in   0700 AM 11/03   0                    
3 WSW Agnew                  5.0 in    0700 AM 11/03   0                    
5 SW Sequim                  4.0 in    0830 AM 11/03   0                    
1 SSE Port Angeles           2.8 in    0700 AM 11/03   0                    
1 SE Sequim                  2.0 in    0700 AM 11/03   0                    
Port Angeles                 1.6 in    0700 AM 11/03   0                    
1 W Port Angeles             1.5 in    0800 AM 11/03   0                    
4 ESE Port Angeles           1.3 in    0700 AM 11/03   0                    

..Jefferson County...
1 SW Chimacum                0.5 in    0700 AM 11/03   0                    
4 W Port Ludlow              0.4 in    0800 AM 11/03   0                    

..King County...
1 NW Snoqualmie Pass         1.4 in    1000 AM 11/03   3100                 
6 WNW Greenwater             1.0 in    0400 AM 11/03   3900                 
Tolt South Fork Reservoir    1.0 in    0815 AM 11/03   2000                 
Eastgate                     0.4 in    0600 AM 11/03   0                    
1 ESE Woodinville            0.4 in    0800 AM 11/03   0                    
1 ESE Woodinville            0.4 in    0925 AM 11/03   0                    
1 NNE Redmond                0.3 in    0800 AM 11/03   0                    
2 WSW Mercer Island          0.2 in    0700 AM 11/03   0                    
2 ENE White Center           0.1 in    0830 AM 11/03   0                    
1 ENE Seattle                0.1 in    0800 AM 11/03   0                    

..Kitsap County...
1 SW Bainbridge Island       0.1 in    0859 AM 11/03   0                    

..Lewis County...
Paradise                     14.0 in   0800 AM 11/03   5130                 
7 S Longmire                 1.0 in    0900 AM 11/03   3770                 

..Pierce County...
Rainier Paradise Ranger Stn  10.0 in   1000 AM 11/03   5427                 
Longmire                     2.0 in    0745 AM 11/03   2762                 
6 W Crystal Mountain         1.3 in    1000 AM 11/03   6410                 
10 WNW Mount Rainier         1.0 in    0900 AM 11/03   3160                 
4 SSW Crystal Mountain       1.0 in    0900 AM 11/03   5240                 

..San Juan County...
8 SE Eastsound               1.3 in    0800 AM 11/03   0                    
4 SSW Friday Harbor          1.0 in    0800 AM 11/03   0                    
5 E Friday Harbor            0.5 in    0605 AM 11/03   0                    
6 ESE Friday Harbor          0.5 in    0700 AM 11/03   0                    

..Skagit County...
18 W Mazama                  2.0 in    0200 AM 11/03   3930                 
5 N Sedro-woolley            1.5 in    0800 AM 11/03   0                    
Concrete Ppl Fish Stn        1.3 in    0640 AM 11/03   195                  
14 SE Diablo                 1.0 in    0900 AM 11/03   4320                 
1 E Mount Vernon             0.5 in    0715 AM 11/03   0                    
Mount Vernon                 0.3 in    0800 AM 11/03   0                    

..Snohomish County...
Brier                        0.2 in    0640 AM 11/03   0                    

..Whatcom County...
Wells Creek Snotel           17.0 in   0800 AM 11/03   4030                 
7 S Mount Baker              14.0 in   0700 AM 11/03   3520                 
12 NNE Hamilton              13.0 in   0800 AM 11/03   3040                 
4 SSE Glacier                12.0 in   0900 AM 11/03   4970                 
12 NW Diablo                 7.0 in    0700 AM 11/03   3630                 
1 E Maple Falls              4.5 in    0700 AM 11/03   0                    
3 SE Bellingham              4.5 in    0700 AM 11/03   0                    
2 SW Bellingham              4.3 in    0700 AM 11/03   0                    
Glacier                      4.1 in    0725 AM 11/03   0                    
2 S Bellingham               4.0 in    0700 AM 11/03   0                    
Mount Baker                  3.3 in    1000 AM 11/03   4210                 
3 NNW Sudden Valley          2.8 in    0700 AM 11/03   0                    
4 ESE Blaine                 2.5 in    0700 AM 11/03   0                    
8 NNE Concrete               2.0 in    0600 AM 11/03   689                  
1 W Lawrence                 2.0 in    0600 AM 11/03   0                    
4 ENE Deming                 1.8 in    0700 AM 11/03   0                    
1 SSE Lawrence               1.7 in    0925 AM 11/03   0                    
2 WNW Ferndale               0.7 in    0700 AM 11/03   0                    
Lynden                       0.3 in    0800 AM 11/03   0                    
Point Roberts                0.3 in    0700 AM 11/03   0                    


  1. Just measured 4.5 inches at about 400ft in south Bellingham. Temp around 31 degrees at 7:45 am.

  2. 4-5 inches overnight on the south hill in Bellingham, elevation 50ft. Still snowing lightly, my black lab is trying to eat it all.

  3. We drove our kids to school today in six inches of snow here in the Upper Skagit Valley. It was awfully pretty, but dangerous. Several cars in the ditch...

  4. About 2 inches on the ground in the hills around Granite Falls. The snow is wet and heavy so we have trees coming down on the roads and on our properties. A few school buses are on snow routes.

  5. I cannot remember accumulating snow ever occurring this early (second week in November is my previous early recollection).
    Could this be a record for some locales ?

  6. Wow, that WRF-GFS model you posted has me getting 4 to 5 inches here on Bainbridge Saturday night! Given that it's just one model run out of many, I'm not going to get super-excited quite yet.

  7. Hi Cliff,

    Just curious how unusual an event this has been for Bellingham? Do you know if this is the earliest significant snow event in recent history? I have only been in town for 18 years, but don't remember any snow before Thanksgiving previously.



  8. It is currently snowing quite heavily in West Olympia near Evergreen State College. Even sticking to our neighborhood street.

  9. I remember the Halloween of 1970 we had snow in the Spanaway/Graham area. We even had snow showers in May of 1971; that was quite a winter we had that year!

  10. This comment has been removed by the author.

  11. Google weather for 98273 Skagit Valley still has sunny with clouds icon lit for today. Its snowing you algorithmic idiots!

  12. 10:00 a.m., snowing on Bainbridge Island. No accumulation of course, but we've lived here 35+ years and I don't remember getting even this light of a dusting this early in the season. But bring it on!

  13. 4 inches or so on E. Victor and Meridian (eastern edge of Columbia Neighborhood in Bellingham at about 10 AM. I woke up at about 1:30 AM and noticed about 3 inches or so. When I went to bed at 9 PM, there was nothing. Apparently there must have been one real heavy shower that put this down.

  14. Where would I find the decoded METAR history like what you showed for Bellingham?


  15. For those wondering if this is the the earliest lowland snow:There have been quite a few snow events in late October and the first week of November.1971,1973,1984,1991 and 2003 are some of the more recent events.The 1984 and 1991 events had strong Fraser River outflows which kept max temps at Bellingham below freezing.And they occurred in late October!

  16. Massive delays at SeaTac today. They kept saying the word unprepared. Was this a surprise change in the forecast?

  17. Snowing pretty heavy right now on Bainbridge. We're pretty close to eagle harbor. Really unusual.

  18. 7:30am South Seattle (Rainier View we had a couple inches sticking on the ground. Drove to Capitol Hill through the rain. Now it's snowing on 15th Ave E & Denny E.

  19. Starting to snow again in Bellevue, at least 10 floors up it is.

  20. Snowing in Kingston at 12:43pm... we're at sea level.

  21. Just before 1pm and snowing at sea level Kingston.

  22. Everything was frosted/slushy this morning in Capitol Hill, and it's been snowing heavily for at least an hour here as of 1pm.

    Would have been nice to have a little heads-up that snow in Seattle was a possibility.

  23. Still snowing on Bainbridge at sea level

  24. It was snowing pretty hard in Olympia for several hours this morning. I had about 2" on my car when I went out at noon. It was sticking to the grass and vegetation and even the streets and sidewalks were slushy. We have a weather station here at our building and the temp dropped from 39 f at 7:00 to 33 f at 10:00. It's now back up to 36. I've lived in Olympia for 24 years and don't remember it snowing this early in the year.

  25. Been snowing light/moderate all day in south bellevue. Also had snow in north Auburn (in the valley!) and still snowing in the kent/auburn area as well.

    Not really sticking near auburn area unless you are on the hill. Only sticking on grass/trees so far in south bellevue from what I can tell.

    I hope this is a sign of crazy amounts of lowland snow this winter, I really like snow!

  26. Just to be sure that we're on the same page, this one isn't the fault of climate change. Right? It doesn't look like Nino, though, since anomaly was positive nearly until the end of October (

  27. Cliff, given the early turn in the weather, any historical indicators we should we all go out and buy snow shoes?


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