February 25, 2023

A Snowy Period Ahead for the Pacific Northwest

 We are currently at the end of the normal lowland snow period in the Pacific Northwest, with the sun rapidly strengthening.   

But not this year.  

The latest forecasts have significant lowland snow over western Washington during the next few days, with many of you experiencing several inches of the white stuff.

And we have an extended, colder-than-normal period ahead.  

Let me give you the details of the forecast.

Today, we have a cold air mass over the region...cold enough to snow anywhere in Washington State.  Temperatures dropped into the teens and twenties in western Washington and single digits in eastern Washington (see low temperatures below).  Several daily low-temperate records fell last night.


This evening a moist occluded front will approach, spreading precipitation over the region.   Snow will move into the Puget Sound region after 8 PM.

Note that the story in the Seattle Times is very wrong, suggesting snow will come in this afternoon around 4 PM.  It also talks about an influx of Fraser River cold air later today.  Simply not correct.

Let me show you the cumulative snowfall totals over Seattle from the most powerful forecast tool available:  an ensemble of many high-resolution weather predictions, each slightly different. (Time is in UTC, 06Z/26 is 10 PM tonight).  A rapid start of the snow around 9 PM.  The black line is the ensemble average....generally a very good forecast.  Just under 1.5 inches.  And it is all over by around 3 AM.


The distribution of snow will be quite varied, so let me show you the accumulated snowfall through 10 AM Sunday (below).

Little snow near the Strait of Juan de Fuca and right on the Pacific Coast.   A Puget Sound convergence zone feature will increase snow east of the Olympics.  Lots of snow in the mountains and a good snow area in eastern Washington east of the Columbia River.  More snow east of Seattle than in the city.

Temperatures will be on the edge for snow.  It will be wet snow and there will be less snow near the water. Note that snow depth will be less than snowfall.  Snow melts and compacts at the surface.


Temperatures will warm into the lower 40s on Sunday (again stronger sun, plus onshore flow after the front).  Thus, I expect the roads to rapidly melt out.

But we are not done with snow.  

On Monday, a low-pressure center will approach the southwest Washington coast, drawing cold air back into the lowlands from the interior.   This low (and associated upper-level trough) will bring more snow into the region, first in western Oregon and then in western Washington.


The 24-h snowfall ending 4PM Monday shows substantial snow over the coastal areas and southwest Washington.  Portland gets several inches.


And then in the next 24-h (ending 4 PM Tuesday),  Puget Sound and Seattle get several more inches.


And folks, this is not the end of the snow threat. 😀

The latest 8-14 day temperature outlook from the NOAA/NWS Climate Prediction Center is enough to make you want to lay in a supply of thermal underwear and hot chocolate.


And if you think what is happening here is unusual, the cold, snow, rain, and winds in California are extraordinary and record-breaking for this time of the year.

9 comments:

  1. Zero to almost no snow in much of our part of Kitsap County. I was ready to shovel sidewalks when I got up. I live along Sinclair Inlet, friend is almost at the 400 foot level, and only a dusting. Weird!

    ReplyDelete
  2. PS I can see snow on the roofs on the Port Orchard side, but not on Manette.

    ReplyDelete
  3. The video coming out from CA today is truly mind boggling, and that's coming on the heels of similar events occuring only a few weeks earlier along much the same areas. If they had only built the additional reservoirs recommended by the Army Civil Corp. of Engineers back in the 70's, so much of their future water worries could be alleviated. Instead most of the precipitation will flow right into the Pacific. We'll then be subjected to more endless stories about Climate Change, while ignoring the human - caused error, once again.

    ReplyDelete
  4. So when did it start snowing in Seattle, and what about that cold from the Frazier River Valley?

    ReplyDelete
  5. As far as Bellingham near the airport is concerned, I would say the forecasts were a pretty big miss on snow amounts. Despite the many days of Fraser River outflows and very cold weather, we only got 1/4"-1/2" of wet snow that quickly melted. The NWS forecasts were also pretty inconsistent and even conflicting for this area. The NWS zone forecasts always indicated very little snow, but NWS posted a winter weather advisory for Bellingham that started with 10" of snow, then it was revised to 4", which was still off. Having these conflicts in the zone forecast and winter weather advisory is a little hard to understand. I appreciate the difficulty in this forecasting and perhaps NWS was a little gun-shy after snow misses to the south, including Portland.

    ReplyDelete
  6. Got a little more than a mere dusting on cars and roofs this morning, spots of slushy, translucent patches of snow on the streets, otherwise, they were wet, but that all is gone now and everything is dry now at almost 1pm. The snow obviously came after I went to bed and was done at some point overnight as it was not snowing when I awoke sometime between 5-5:30AM.

    ReplyDelete
  7. 3" above Hood Canal, started about 9 or later and finished up around 4 am.

    ReplyDelete
  8. This prediction was much better for the Olympic Peninsula coast than NWS. NWS said we would get maybe 2".... we received about 6" on 2/25.... same with the December storm where we were predicted 3" and received 12"...

    ReplyDelete

Please make sure your comments are civil. Name calling and personal attacks are not appropriate.

More Wildfire Misinformation at the Seattle Times

 The Seattle Times continues to shamelessly exaggerate and hype the regional effects of climate change. This week they really went overboard...