Friday, February 23, 2018

Going to Snow Around Puget Sound Very Soon!

It is 1 PM and snow is heading towards Puget Sound during the next few hours.

Weather radar  (at 1:05 PM) shows a modest front, with associated precipitation, approaching  the coast (see image).

You can also see the front in the latest visible satellite imagery:


The air is PLENTY cold to snow.  The latest observations at SEA-TAC airport show the temperature is -10C at 850 hPa (about 5000 ft) and below freezing pretty much down to the surface (see temperatures and winds below in a time-height cross section)

And the air is quite dry.  That is important because precipitation falling into the cold air will evaporate (sublimate) and cool.

The only issue is how much.    There we have a problem for snow lovers in Seattle.  The winds are westerly/northwesterly approaching our region and this will result in a rainshadow (or in this case snowshadow) in the lee of the Olympics over central Puget Sound.

Our snow will be light....not much more than about a half-inch around Seattle, with more north and south.  Here is a forecast of the 24-h total precipitation (ending 4 AM Saturday).  You can see that pesky rain shadow.  There will be plenty of snow in the mountains, and several inches over parts of NW Washington.  The Kitsap will get several inches.


Anyway, a least the Seattle commute will not be too bad with the small amounts expected...but be careful in any case.

14 comments:

  1. Looks like yet another tease. Oh well!

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  2. Right now in Federal Way, 36 degrees with winds out of the SW, but dewpoint about 20. We will see!

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  3. The sun just came out in the Convergence Zone.

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  4. Snowing hard in Lacey right now, near Cabelas.

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  5. It looked threatening and was windy up in Sequim for a bit, and then the clouds broke up and we are ending up mostly sunny late in the afternoon. Radar shows nothing substantial coming as of 5:30PM.

    After 8+ inches this last week, I think this one is a bust, and it came from a direction where we weren't shadowed.

    Can't win the snow lottery every time.

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  6. Yesterday the pinpoint forecast for Snoqualmie Valley predicted anywhere from 9" to 22" accumulation by Monday depending on location and elevation.

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  7. 6 am Sat. 11 inches of snow on the ground and still snowing in Eastern Whatcom County.

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  8. 5 1/2 inches above Lake Samish south of Bellingham.

    Steven

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  9. Maybe an 1" near the Bellingham Airport. Only a few flurries this morning. Hopefully we are past significant winter weather and frigid Fraser River outflows. For us, this winter has been much milder than the 2016-17 winter and much closer to the 2015-16 winter before that. December and January winter weather was very mild with the only thing being a surprise snowfall and freeze in early November before Thanksgiving and a freezing rain episode in late December, which did not affect us much but hit the northern part of the county quite hard. Maybe this most recent February freeze will be enough to kill the aphids and insect pests trying to winter over.

    We are recent immigrants from Seattle. Wind is the issue here, not cold. 50 - 60 mph at the airport is surprisingly common. I worry about it a lot less than I would have in Seattle, but that is probably a false sense of security given the abundance of trees here.

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  10. Yesterday, perfect snow at Stevens but you had to get there before 8 am for fresh tracks; avalanche control closed the road from 8 til almost 10. Today, lots of new snow but all lifts are closed until 10 am due to high winds. Then they will re-evaluate. This is wild weather.

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  11. Just got back from Vancouver Canada, we had 6 plus inches on Friday. Pretty wild walking on the snow covered beach on Sat.

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  12. Is this a result of the polar vortex spitting in two with polar temps above freezing?

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  13. Negative 21 in the arctic currently. I guess we're ok for now.

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  14. Vortex is still split with the warm patch shifted east of Greenland. Note: North Pole was above freezing two days ago. Europe is getting clobbered with cold temps now. Again, is the western vortex causing our cold weather just like in Europe.

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