Sunday, February 3, 2019

The Snow Band Approaches

The snowband advertised by the models is now approaching the coast and should swing inland during the next few hours (indicated by the arrow on the infrared satellite image at 9 PM). The low pressure system, indicated by the circular swirl of clouds, is west of southern Vancouver Island.


Really cold air (single digits to teens) is pushing toward Bellingham, with gusts to around 45 mph.  Brutal stuff.  And temperatures in most of the rest of western Washington are in the low to mid-30s.


The latest WRF model run swings the precipitation band through overnight, dropping about 2-4 inches around central Puget Sound (see 24 hr snowfall ending 4 PM Monday).  Much more north of the Olympics and in some locations of SW WA.


The NOAA HRRR model has a similar solution:


And the UW ensemble system, initialized Sunday morning suggests about 1.5 inches overnight:


I can't stress enough that snowfall is not the same as snow accumulation.  After a warmer than normal January, soil and roadway temperatures are relatively warm.  You can see that by looking at the latest air and roadway temperatures from the City of Seattle's SnowWatch website (see below).
Even with near-surface air temperatures at freezing or below, the road temperatures (in the boxes) are well above freezing.  With the help of some deicing solutions (spread by SDOT and WSDOT), I suspect the main roadways will be fine tomorrow morning as long as the air temperatures remain above the mid to lower 20s...and they will. 


13 comments:

Charles Primm said...

You note "brutal" weather predicted for Bellingham but you don't mention Vancouver, our closest big neighbor to the north. Why not?

Stephen Fry said...

Thanks for the update Cliff! Even though I follow forecasts, I was surprised to see it snowing and sticking in N Seattle @ 2:30 pm today, while returning from wood smoke patrol. My past unpublished review of Seatac wx data and Forks soundings (~ 30 years ago) showed we usually needed moderate ~ S/SW winds, cool temperatures (usually less ~ 42 degrees F, at the surface, colder at 850 mb) the day before a > or = 1-inch snow event at Seatac. So in theory it shouldn't snow one inch or more at Seatac today (2/3/19), since there was no ~ SW wind and it was too warm on Saturday (2/2/19); but will be a possible event (@ Seatac) tomorrow (2/4/19) (if today's Seatac temperatures didn't exceed ~ 45 degrees F). It appeared that the wind was moderately strong from the ~ south in Magnolia and N Ballard today. I've misplaced or lost my ~ 30 yr old Seatac snow event handwritten research, so the above info is based-on my memory. Maybe I will find the paper records (which evaluated ~ 10 parameters or more for a few decades), which I did on my own time - since weather fascinates me and I was frustrated with erroneous snow forecasts (being a long-time native and resident of the Seattle metropolis).

ryamkajr said...

I am just glad this snow event happened before you started posting about "meteorological Spring" and whatnot.

It is nice to finally have a little bit of winter.

ChrisC said...

Uh, we've had snow accumulation of an inch or so in Seattle since mid-afternoon.

cgt said...

Lots of black ice/wind experienced driving home from Ferndale to Bellingham after a lame superbowl game.
What a boring game, current weather here is more exciting with 18 degrees and high winds, settling to a steady 21, with substantial winds heading south to Bellingham.

Now 3 hours later, 18 degrees, a few gusts with maybe a proud inch on the ground.

Shahob Mousavi said...

-6F with wind chill here in Bellingham, steady snow still coming down. Roads dont seem safe but lovely watching the storm from inside.

BAMCIS said...

A Zamboni will probably go past my house before the plow/grit truck does. Good day to just stay home and take it easy.

TW B said...

Looks like Euro Model nailed it! Again.

Jonathan Doe said...

Overnight minimum temperature of 14.7F at my location in NW Bellingham. I'm sheltered from the north so only measured a max wind gust of 25 and wind chill of 3.

Zac Smith said...

Out here in Woodinville I'm headed to at least a foot (10 already). Uncertainty indeed!

Rabbits' Guy said...

The Bow weather rock has about a 4" layer of white fluff with still a slight dribble coming down at 9:00 AM. 20 degrees. No wind happened here - facing NE.

Ward said...

It's 24F in Shoreline, about 4" of snow on the ground, blowing snow, and the roads are quite frozen.

Unknown said...

Hi Cliff,

From the west side of Renton, we had drifts as high as 10 inches. Incredible!