textproduct: Seattle/Tacoma

SYNOPSIS

A frontal system this afternoon continues to spread precipitation across Western Washington with breezy winds and mountain snowfall. A compact system will track northwards into southern Vancouver Island and Olympic Peninsula tonight for additional rain, mountain snow, and gusty winds. Another frontal system tracks inland near the Columbia River Friday morning. The active pattern continues over the weekend.

LONG TERM /SUNDAY THROUGH WEDNESDAY/

Guidance suggests the active pattern continues over the weekend with another weather system tracking across the Pacific Northwest on Sunday. For those looking for a period of potentially drier weather (raises hand), ensembles suggest late Monday into Tuesday may be the best chance, with that said, lingering precipitation chances exist in the NBM, currently in the forecast. Another system looks to track towards Western Washington during the middle of next week. Temperatures will generally be near normal early next week. JD

AVIATION

Southwesterly flow aloft this afternoon as an upper level trough continues to approaches W WA. S/SE winds increase this evening with gusts possible up to 25-35 kts for all terminals, generally looking to peak through the overnight period into early Thursday morning. Terminals along the coast (KHQM) could see upwards of 40-45 kts of wind gusts, especially this evening into the overnight hours. S/SW low level wind shear around 2000 feet can be possible later this evening. Gusty winds will start to decrease by 16z-18z turning more southwesterly with gusts diminishing by the afternoon.

MVFR/IFR will likely continue into Thursday morning as steady low level moisture keeps conditions limited across the area terminals.

KSEA...S/SE winds will start to pick up later this evening after 06z with gusts upwards to 25 to 30 kts. Latest guidance continues to show concern for low level wind shear around 2000 feet with strong SW winds aloft. Winds look to peak at the terminal early Thursday morning 10z-15z with gusts possible up to 35 kts, as winds will start to transition to a more southwesterly direction by late Thursday AM (15z-18z) but will remain breezy. MVFR/IFR conditions will continue into Thursday.

MARINE

We're in a period of very active weather here across the region. Headlines are in effect across all waters with a lot at play. Starting with the Storm Force warnings, frequent gusts of 48+ kt have been observed across the coastal/East entrance this afternoon. There will be a lull this evening as a front passes, but an additional system is favored to bring a westerly burst of strong winds late overnight into early Thursday morning. These headlines are scheduled through midday Thursday, at this time. Elsewhere, gales are posted for the West/Central Strait along with the Northern Inland waters as well as Admiralty Inlet through Thursday as well. A SCA is currently in effect for Puget Sound but a transition to gales here also are in the cards tonight through Thursday morning.

An additional weather system is expected Thursday night into Friday with the potential for more headlines. This disturbance has trended further south towards the mouth of the Columbia so the strongest winds are to be over the OR coastal waters. Nevertheless, an active pattern is likely to remain over the weekend and possibly into next week, bringing an additional period of stronger winds.

Seas remain elevated, holding around 17 to 20 feet tonight. They are expected to build again into the 20-25 ft range over the coastal waters on Thursday, fluctuating through Saturday between 15 to 25 ft before finally settling before 10 ft on Monday.

McMillian

HYDROLOGY

A series of systems will move through Western Washington through the weekend. The most hydrologically significant system will be the atmospheric river this afternoon through Thursday. Generally, three to five inches of precipitation over the Olympics are expected during this timeframe, which will push the Skokomish into moderate flood stage into Thursday. The Bogachiel and Satsop will also be under pressure in this scenario but latest guidance has the Bogachiel just under minor flood stage.

While precipitation will be less with the systems beginning Friday the lack of much of a break will keep rivers over the Southwest Interior rising into the weekend. It's possible that the lower reaches of the Chehalis could flood late Friday into Saturday. The Skookumchuck near Bucoda and the Newaukum near Chehalis could reach action stage Friday into Saturday.

Rivers across the remainder of the area will also be on the rise in the next few days but the combination of a little less precipitation and a little cooler temperatures in the Cascades will reduce the flood threat for rivers flowing off the Cascades.

With all of the precipitation the landslide threat will continue to increase into the weekend. Felton/Mazurkiewicz

SEW WATCHES/WARNINGS/ADVISORIES

WA...Wind Advisory until 10 PM PST this evening for Admiralty Inlet Area-San Juan County-Western Skagit County-Western Whatcom County.

High Wind Warning until 1 PM PST Thursday for Admiralty Inlet Area-Central Coast-North Coast-San Juan County-Western Skagit County-Western Whatcom County.

Wind Advisory until 10 AM PST Thursday for Bellevue and Vicinity- Bremerton and Vicinity-East Puget Sound Lowlands-Everett and Vicinity-Hood Canal Area-Lower Chehalis Valley Area- Seattle and Vicinity-Southwest Interior-Tacoma Area.

Winter Storm Warning until 4 PM PST Thursday for Olympics.

Flood Watch through Friday afternoon for Eastern Strait of Juan de Fuca-North Coast-Olympics-Western Strait of Juan De Fuca.

Coastal Flood Advisory from 5 AM to 2 PM PST Thursday for Eastern Strait of Juan de Fuca-North Coast-Western Strait of Juan De Fuca.

High Surf Advisory until 10 AM PST Friday for Central Coast- North Coast.

Coastal Flood Warning from 5 AM to 2 PM PST Thursday for Central Coast.

Winter Storm Warning until 10 PM PST Thursday for West Slopes North Cascades and Passes-West Slopes North Central Cascades and Passes-West Slopes South Central Cascades and Passes.

PZ...Small Craft Advisory until 4 PM PST Thursday for Grays Harbor Bar.

Gale Warning until 10 AM PST Thursday for Admiralty Inlet- Central U.S. Waters Strait Of Juan De Fuca-Northern Inland Waters Including The San Juan Islands-West Entrance U.S. Waters Strait Of Juan De Fuca.

Storm Warning until 1 PM PST Thursday for Coastal Waters From Cape Flattery To James Island 10 To 60 Nm-Coastal Waters From Cape Flattery To James Island Out 10 Nm-Coastal Waters From James Island To Point Grenville 10 To 60 Nm-Coastal Waters From James Island To Point Grenville Out 10 Nm- Coastal Waters From Point Grenville To Cape Shoalwater 10 To 60 Nm-Coastal Waters From Point Grenville To Cape Shoalwater Out 10 Nm-East Entrance U.S. Waters Strait Of Juan De Fuca.

Small Craft Advisory until 10 PM PST this evening for Puget Sound and Hood Canal.

Gale Warning until 10 AM PST Thursday for Puget Sound and Hood Canal.