January 08, 2018

Snow in Mountains, Wind, and Ample Precipitation: A La Nina-Like Pattern This Week

For those worried about the Cascade snowpack, salvation is at hand:  the atmospheric circulation is taking a turn towards more of a La Nina pattern, with cooler/wetter/windier conditions prevailing this week.

The upper level flow pattern for Wed and Thursday at 1 PM is predicted to include an offshore ridge and northweserly flow over the NW, with some disturbances moving SE in the cool flow.  Much more La Nina-like than we have seen in a while.

As a result the models are forecasting a major snowfall over the Cascades, BC, and NE Washington as illustrated by the 72 hr snow total ending 4 PM Thursday. We are talking about 1-3 feet above 3500 ft.

And we could get blustery on Thursday as la ow center moves into southern BC during the afternoon, with large pressure gradient established over WA (see below).    Haven't seen  too many of such vigorous systems this winter.

Precipitation? Substantial...but not enough for real flooding.  The 72 hr total ending 4 PM Thursday, show 2-5 inches over the mountains and about 1.5 inches over Seattle.


  1. Maybe some snowpack building in the medium and higher elevations of the cascades,but it sure doesn't look like a typical La Nina winter in the lowlands.It seems to be a nearly continuous cycle of ridging followed by mild,sluggish southwest flow this year.No dynamic NW flow or strong Arctic air outbreaks.This winter reminds me of 1999-2000,which ended up being a big La Nina bust.Although there still is a chance that some interesting winter weather might occur in February/March,like what has happened in some previous winters,such as 1989.

  2. John, I remember that cold snap in February 1989. Alaska had had record cold for weeks and that arctic air moved into our area rapidly. If I remember correctly, the day the cold air arrived our temperature dropped from the low 50s in the morning to about 20 by midnight.

    1. The temperature drop happened between the 30th and 31st of January, then continued to drop, with a high temperature of 17 on February 2nd. I remember it very well, it was my 21st birthday and no one would go out to have a celebratory legal drink with me!

  3. This morning, Jan. 9, it's been raining non-stop at my house in Woodinville for hours, heavily at times. Dark and gloomy all around. So I'm checking the radar(Accuweather and RadarNow!)to see if there is a chance to take the dogs for a walk later. No precip is showing at all in the greater Seattle area. What is going on?

  4. Been dumping hard in the BC interior to start the week and looks to continue until Friday... Though forecasts suggest an alpine warm up rolling in on Sunday with very high freezing levels?

  5. There is a big difference between "snow in the mountains" and actual quality snow for recreation. This is just another storm that may have brought some snow but also at increasing freezing levels with temps at baker already reaching 34F at 4K ft. Another foot of cascade slop and poor quality conditions. Not really a La Nina storm IMO where is the 2500ft freezing levels and consistent cold temps? Big alpine warm up coming by the weekend also. Very disappointing season overall


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