The latest radar indicates showers along the coast and over NW Washington, all of which are reaching the surface as rain. A few snow flurries have been noted around the region.
The latest sounding above Sea-Tac airport (12:30 PM) shows a freezing level around 950 ft, which means the atmosphere is now close to cold enough for snow to reach sea level. This morning's model output suggests some warming aloft this afternoon.
I am also concerned that the upper level pattern (see 500 hPa heights below for 1 AM Sunday) looks fairly close to the canonical snow pattern.
In such a situation difficult, rapidly changing situation, one turns to the HRRR...the constantly updated NWS High Resolution Rapid Refresh model. The 1-h snow forecast ending 4 PM shows snow reaching the surface over NW Washington.
This is an extraordinarily difficult forecast because the temperatures are so close to the line for rain versus snow. The classic western WA dilemma. And above is only one solution. There are large uncertainties in the model solutions (see NWS Short Range Ensemble Forecasts of total snow) for Seattle from nearly no snow to several inches.
The bottom line: there is a good chance of snow showers later this afternoon and evening, particularly north of Everett. As the atmosphere cools down further later this evening and a convergence zone sets up, several inches could fall north and east of Seattle after midnight. Will have to watch this situation very carefully during the afternoon, as my colleagues at the NWS will certainly be doing.
Lots of flurries all day in N. Tacoma. Nothing sticking.
ReplyDeleteIt's been snowing here in West Seattle for about 45min now, off and on. Thanks for the update!
ReplyDeleteModerate snow with minor accumulations on Vashon Island. 34 degrees.
ReplyDeleteGetting some light snow right now (2PM) just west of Lake Sawyer.
ReplyDeleteLight snow starting now in Forest Hills east of Factoria :)
ReplyDeleteSnow falling from 2Pm in South Seattle, not sticking as of yet
ReplyDeleteSnow showers started at 1:00 pm in Newcastle at 400 ft (Olympus hill). Very small flakes and 35F temp so not sticking.
ReplyDeleteOops, I meant to say 2:00 pm.
ReplyDeleteLooks like some snowy areas just as the New Year's Eve revelers head home. This may not end well for a few folks.
ReplyDeleteSnow began at 2:30 pm 2 miles southwest of North Bend, at 1100 ft elevation.
ReplyDeleteSnowing lightly in Bellingham since about 1:30 pm. Sticking away from the water, about 1/2 inch so far.
ReplyDeleteBeen snowing pretty hard since 11:00AM at Maple Falls, WA - 25 miles due East of Bellingham. 600 foot elevation. About an inch accumulation.
ReplyDeleteTop of Finn Hill/Juanita Drive just started snowing
ReplyDeleteSnowing steadily in Carnation as of 6:30pm.
ReplyDeleteStarted blowing out of the South pretty hard with rain around 330 in Tacoma today. Had been snow most of the mid day until 1pm. Afraid it's going to flash freeze once it clears off later. Hoping for snow
ReplyDeleteHad snow in Redmond for a couple of hours. Made a nice slush everywhere, cars, roads, etc.
ReplyDeleteSnowing in Olympia @ 1218 am
ReplyDelete0 to 10 inches fell in Metro Vancouver.
ReplyDeleteGot about an inch so far in Duvall. Ended about 30 minutes ago. Started around 4:30 pm as a mix, then eventually, around 6, switched over to mainly snow.
ReplyDeleteApproximately 1" here in Eatonville this morning...light breeze and 32°F
ReplyDeleteApproximately 1" fell overnight here north of Eatonville...32°F
ReplyDeleteIt looks like the cold snap will not continue as long as originally advertised unless the predicted warm-up next week-end is short-lived.
ReplyDeleteAnd not as cold, either. Typical.
DeleteTalk about hit or miss.
ReplyDeleteZero snow in Auburn, but in burien/sea-tac just west there's 5+ inches.
No model, even the HRRR picked up on the convergence that far south even when the event was 6 hours out. It had the band well north of Sea-Tac (Everett-N-Seattle). Amazing the micro climates and topography and geography around here influencing weather patterns. Had that band set-up shop 5 miles north of the Airport and there would
ReplyDeleteHave been little problem with all the whiners at the airport. I do think many airlines should have known the inherent uncertainties in the forecast as the band formed between 4am and 8am dumping near 6 inches in a very narrow band-area. This post was spot-on. At that point all you can do is NOWCAST and that's hard for airlines who seemed to have majorly been caught of guard. Well done Cliff.
Still going 5 years since the last real snowfall around the region. It doesn't look like this cold spell (I won't say snap since we'll be over freezing through most of it) is going to do it either.
ReplyDeleteYep. I don't count it as "cold" unless the high is below freezing nearly everywhere and certainly at Sea-Tac. This is a cool spell, not really cold. Disappointing.
DeleteCliff, can you please please do a blog on how or why Mission Ridge received 39 inches of snow in 24 hours? That is almost unheard of for that area, especially when only a few inches were forecast, and surrounding areas like Stevens, Snoqualmie, Leavenworth and Ellensburg got virtually nothing. Looks like Blewett Pass also got about 15 inches, so was this just confined to the Wenatchee mountains? I'm baffled by this and would to hear what caused it. Thanks!
ReplyDelete