December 12, 2009

A More Detailed View

This morning's run is now in. Today will be snow free for most of western WA...only the Portland suburbs could see a few snow showers and some freezing rain.

The new model runs are somewhat more threatening for the Seattle metro area. The front associated with the upper shortwave (see figure) will come in mid to late afternoon. It is producing more of a trough/low at the surface then earlier runs and now the model suggests light snow over central Puget Sound (see graphic). Not a lot, but enough to whiten the place. Timing--starting roughly 3 PM and continuing for three to six hours. Then whatever snow is left would be in the Puget Sound convergence zone north of the city.

Next threat will be Monday evening with the warm front--could start as snow, with only NW WA getting anything significant (few inches) before it turns to rain as the air warms up.

So today is fine...hit the malls, visit friends, or go to your favorite concert or activity.
Tomorrow is ok till roughly 3PM. Then be careful...this is not going to be a big snowstorm--an inch or two at the most.

Monday is fine. Monday night when you are home there could be some light snow turning to rain Tuesday AM. Commute will be fine Tuesday.

PS: I will be giving a public lecture--"The Secrets of Snow"--at Third Place Books in Lake Forest Park on December 17th at 7 PM, followed by a book signing. In this talk I will describe the unusual circumstances that have to come together for us to get a big snowstorm, details of convergence zone snows, the Fraser River Gap flow, arctic fronts, and more. My favorite topic


  1. As always, I'm glad I check Cliff's blog first & last before I believe ANYTHING the local weather station reports tell me (or that my neighbors base their "reports" on). Sigh.

    I don't get excited anymore by the word "snow"... I'm just laying low & waiting. Hoping it will happen. The sled is in the garage for my 3 & 1/2 year old. I bought a snow shovel - just in case (since I'm a new Seattle resident, it seemed a good idea to at least have one). My pantry is always generally full (did I mention I have a 3 & 1/2 yr old?). I drive a Subaru. Guess I'm about as prepared as I can be.

    Having lived in Buffalo NY & Harrisburg PA, I can say that we are far less "ready" for real snow here. But that's ok, b/c we don't get "real snow" do we?


  2. Loved this blog Cliff. Informative, yet short and to the point with no sign of any hype.

    Also, may I say, I like the trends of the models. Bringing a little more precip to the central sound.

    Will be interesting to see how it all plays out. One little thing, can make a big difference.

  3. A voice of reason that can be heard over the din of weather-scarers... thanks Cliff!

  4. @Smiling, we got real snow last year that lasted several weeks even on the roads, where it turned into snowy ice, because we DON'T have a real snow removal plan, nor do we have adequate equipment or facilities. We also have plenty of steep hills that would be tricky even with good gear.

    I grew up in northern New Jersey, where municipalities WERE ready and able to remove snow and keep roads clear. Here, not so much.

    Be careful about venturing out here if we do get snow... nobodoy knows how to drive in it, and the SUV folk especially seem to believe that they are invincible. They haven't learned that going fast doesn't mean stopping fast!

  5. Thanks Cliff,
    I grew up in the Midwest where every Christmas was white, so a little snow around the holiday is always grand.

    Just found out your blog is an app on the iPhone...GRAND!!!

  6. Cliff

    First off, thanks for your forecasts! As a skier I have developed a constant need to know what's going to happen with the weather and your site is a great resource.

    It's been a while since we've had any precipitation, and I'm wondering if the incoming precipitation is going to make for good skiing conditions this week, or if it's going to get too warm for most of our ski areas. It would be awesome if you could touch on this at some point!

  7. The first flakes have started in Bothell at around the 370 foot elevation.

  8. 9:15am Lake Stevens approx 300' and 29f. We recently had a Winter Weather Advisory issued as well.

    Light snow with accumulation of about 1/4" right now on the roads and everything. It's been picking up speed the last 30 minutes.

    Watching the radar images it looks like this might keep going for quite some time today.

  9. I lived a winter in Anchorage. Now that city was ready for real snow

  10. All,
    Snow flurries outside my window now...all I need now is some hot cocoa!..cliff

  11. The winter weather advisory which was suppose to start taking affect at 4PM today, is in effect now.

    Wonder where this non-predicted moisture is coming from?

  12. Nice plump snowflakes coming down here in Mount Vernon at 10:45am. Beautiful!

  13. Snow flurries in North Tacoma. Very small flakes.

  14. Noon: snow flurries, 500 ft, between Renton and Maple Valley. Pretty!

  15. Tiny flakes have been drifting down on and off, since about 9 a.m. No accumulation yet. Keeping fingers crossed: I had enough of s**w last year.

  16. 30 in West Oly with light flurries...and I do mean light. Come on! It will have to do better than this for a 2 hour late start tomorrow!!

  17. In my opinion, there is quite a "Snow Shadow" over the immediate Seattle-Bellevue-Isaaquah Region. Hope this changes later :( Actually, some sunshine coming through here in Issaquah @ 800 ft. Saw two flurries today, thats it!

  18. Just started here in South Bellevue - Newcastle a few minutes ago. Light flurry, sparse small flakes.

  19. Major snow shadow currently happening over the Seattle/North Bellevue/Redmond area. This sucks. :(

    Hopefully the arctic front, or CZ, can deliver later this afternoon/evening/tonight.

  20. snowing and sticking in Olympia, South Capitol Neighborhood

  21. @Brian, I am with you. Once my children leave my house, I am quickly moving to a region with more predictable weather. The shadow thing, I have found, bugs me to no end. It seems to always be there when I want snow, but never seems to stop the rain. Hmmm.

    I've been telling my kids all week not to listen to the news -- they get too excited and hopeful that they will be able to watch snow fall.


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