Another 2-5 inches of snow are possible in the greater Puget Sound area through Monday evening, but snow totals will be highly variable.
Winter Storm Warnings remain in effect for a wide area of Western Washington, including the greater Seattle Metro area until 10 p.m. Monday as a storm moves into the region combined with arctic air already entrenched.
Travelers should expect low visibility and potentially slick roads. The snow is expected to fall in spurts through around 10 p.m. then taper off toward midnight as the storm moves away.
In addition, winds are expected to increase into the evening, gusting as high as 20-30 mph, making for low visibilities.
Some schools are already delaying classes for Tuesday. Get theSee full school delay list.)
The snow has caused several traffic problems around the Puget Sound area:
* I-5 and I-405 was snarled across much of the Seattle-Bellevue and Renton areas and it was particularly bad in the Tukwila area.
* The Seattle Department of Transportation has shut down the Alaskan Way Viaduct due to treacherous conditions.
*A semi jackknifed across I-5 South at S.188th in Tukwila around 3:30 p.m., briefly closing all lanes.
* A bus lost control and slid across the lanes of the Battery Street tunnel, closing the southbound lanes there
*SR-518 had to be closed near SR-99 to clear multiple spin-outs.
*The West Seattle Bridge was also a virtual parking lot as of 4:45 p.m. as slick roads made it difficult to get over the bridge.
* Side streets around Seattle were jammed as people tried to reach the freeways to get home.
Also, a Boeing 747 cargo plane slid off the end off the end of the runway at Sea-Tac Airport Monday evening, causing delays there.
Earlier in the day in Pierce County the eastbound lanes of SR-16 were closed just west of the Narrows Bridge due to numerous crashes, and a Pierce Transit bus rolled over on the UW Tacoma campus, injuring several passengers.
Multiple Weather Events In Play This Evening
A very complex weather situation is setting up as a very cold area of low pressure slides through Western Washington, with several major factors contributing to snow in the Seattle Metro area.
First up, a Convergence Zone is setting up shop right over the Seattle metro area. This is due to strong north winds from the Fraser Valley colliding with southerly winds being brought up by the passing storm. As the winds collide, it causes the air to rise and condense into clouds and, in this case, snow. Although this is not a classic Puget Sound Convergence Zone, which is when winds come west down the Strait of Juan de Fuca and turn south toward Everett as southerly winds collide. But the fact that winds are colliding is enough in this case, no matter where the northerly component is coming from. Convergence Zones can be great snow-makers and the Seattle area needs to be on guard as we could accumulate 1-4″ by the evening or more.
Second, the storm’s center is bringing its own moisture along for the ride, so expect enhanced snowfall for other areas outside of the Seattle Metro through the evening through about 5-6 p.m. These cells could bring 1-3″.
Third, cold winds continue to blast out of the Fraser River Valley, gusting as high as 50 mph and could strengthen to gusts of 60 mph this evening. At 4 p.m., Bellingham was 21 degrees with a 57 mph wind gust for a wind chill of -3. Friday Harbor reported blowing snow and gusts to 47 mph. A High Wind Warning remains in effect for western Whatcom County and the San Juan Islands through 4 a.m. Tuesday. A lesser Wind Advisory is in effect for Island County. western Skagit County and the Admiralty Inlet area for gusts to 50 mph.
This winds are running across the Salish Sea and into the eastern Strait of Juan de Fuca where they are running into the Olympic Mountains. This is the inverse rain shadow, per se, and this rising air is squeezing out all sorts of moisture along the northern Olympic Peninsula, where snow totals from Joyce to Port Townsend are reaching 6-12″ and more is falling.
Fourth, these strong winds will continue to filter south into the Puget Sound region later, meaning we’ll add gusty winds to the equation as high as 20-30 mph this evening, making for blowing snow a possibility.
Fifth — and this too is important — a very cold, unstable air mass is moving in behind this storm. If you thought it was chilly outside now, there is even colder air behind it. In addition, this storm briefly pulled up a little warm air from the south — thus the hail at Sea-Tac Airport earlier today and temperatures in Tacoma briefly warming into the mid 30s. But this “warm” air has added some fuel to the system and could cause stronger development of these individual cells.
Thus as we get later into the evening, the steady snows may taper off, but we’ll see these roaming snow showers and they could be quite intense, with thundersnow a possibility. This would be more in the 7-10 p.m. time frame. These cells will be random in nature and fairly compact, geographically, but where they strike, they could put down a few inches in a very short amount of time with whiteout conditions (plus the thundersnow). But a few miles away, it might be nothing. So all areas need to be prepared for intense snow showers through the late evening.
Temperatures will be below freezing through the event, with temperatures dropping as we head further toward midnight with lows gradually dropping to near 20.
When does the snow end?
Everything should taper off by 10 p.m. to midnight, with some individual snow showers/thundershowers possible through the night.
Watch the snow accumulate
Dr. Dale Ireland out in Silverdale had his camera rolling and, as tradition, used his original 2001 Ichiro bobblehead as a snow measuring device. Watch the snow accumulate today!
From Snow To Ice Box
As the night progresses and the storm continues to move south out of the region, even colder air will push into the Northwest. As we mentioned, lows Monday night will be in the upper teens to low 20s.
Tuesday will be dry but bitter cold, with breezy north winds continuing. Highs will not make it out of the 20s.
The National Weather Service noted that since 1985, we’ve only remained below freezing all day long in November just once in Seattle. Tuesday will mark the second day in a row.
A very bitterly cold night expected Tuesday night as lows drop to between 5 and 15 degrees, with some spots in Eastern Washington going well below zero.
We begin to warm up Wednesday a little, then closer to normal for Thanksgiving with a more old-fashioned rainy day. It might briefly start as snow, but won’t last long.
Seattle Colder Than Barrow, Alaska
Just how cold is it in Seattle? Afternoon temperatures were around 28 degrees. Meanwhile, up in the northern reaches of Alaska, Barrow reported a high of 34 degrees Monday. But that is all related. A very large ridge of high pressure has built into Alaska, shoving the jet stream way to the northern arctic reaches. The jet is then diving back down the east side of that ridge into the Pacific Northwest — in essence creating a conduit for air from the Arctic Circle to channel south into our area.
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Snow totals so far:
Here are some snow reports that have come into the KOMO News room and National Weather Service as of 6:20 p.m. (Some may be more now)
- Elwha: 11.0″
- West Port Angeles: 10.0″
- Enumclaw: 9.0″
- North Bend: 9.0″
- Port Angeles: 8.5″
- Mount Pleasant: 7.6″
- Coville (Clallam Co) 7.0″
- Sequim: 7.0″
- Enumclaw: 6.2″
- Port Townsend: 6.0″
- Tacoma: 4.5″
- Kingston: 4.0″
- Potlatch: 4.0″
- Federal Way: 3.9″
- Covington: 3.5″
- Hoodsport: 3″
- Coupeville: 2.1″
- Port Orchard: 2.0″
- Vashon: 2.0″
- Edmonds: 2.0″
- Marysville: 2.0″
- Renton (East Hill): 2.0″
- Freeland: 2.0″
- Oak Harbor: 2.0″
- Puyallup: 1.9″