textproduct: Seattle/Tacoma

UPDATE

Stout onshore flow across the area due to FROPA. In the front's wake, showers continue to stream into W WA as the day winds down. Gusty winds have also been observed with gusts up to 35 mph at Paine Field and 38 mph at West Point within the last hour or so. Wind gusts will gradually decrease tonight but showers are to persist though spotty in nature. Overnight lows are to bottom into the upper 30s to lower 40s. The previous discussion remains below along with an updated marine/aviation section:

SYNOPSIS

A strong storm will continue to bring wind, rain and high elevation snow today. Post frontal showers and a convergence zone will follow on Wednesday. Drier conditions and slightly warmer weather through the weekend. Troughing returns on Monday for rain and cooler temperatures.

SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/

A strong Pacific storm system continues to move throughout the area this afternoon, bringing gusty winds, mountain snow, and lowland rain. Recent radar imagery shows the bulk of the precipitation band sagging eastward, with most of the northwestern half of the CWA dry. Rivers may see small rises but additional flooding is not expected. Breezy southerly winds have arrived this afternoon, more notably in areas along the coast and especially up in the North Interior near Whidbey Island where we are seeing gusts up to 45 mph. Winds will generally remain breezy throughout the rest of the evening, upwards to 30 mph at times. Snow levels remain high this evening limiting snow up to the high elevations, primarily in the Cascades.

Heading into Wednesday, we'll be in a post frontal airmass with showers lingering throughout the area. Snow levels will lower down to 2500 feet, with some accumulations expected in the Cascade Passes. A convergence zone will also develop late Wednesday afternoon primarily over Snohomish County. This convergence zone may locally enhance snow accumulations further, especially at Stevens Pass where we could see a range from 8 to 12 inches. A winter weather advisory is in effect for Stevens Pass, and also the North Cascades. With the air mass being unstable as well, SPC has put most of western Washington in a general thunder risk. Could see an isolated thunderstorm or two.

Lingering showers possible on Thursday, but will trend drier throughout the day. Snow levels remain low, around 1000 to 1500 feet, which could bring a very brief rain/snow mix to the Cascade foothills Thursday morning, but confidence is low.

LONG TERM /FRIDAY THROUGH TUESDAY/

High pressure will build into the area starting on Friday and throughout the weekend, bringing warmer and drier conditions to western Washington. High temperatures over the weekend in the upper 50s, even possibly reaching the lower 60s at times. A trough will return early next week for cooler temps and more rain.

Mazurkiewicz

AVIATION

Strong southwest flow aloft will continue into Wednesday morning before easing slightly. Surface winds remain south to southwesterly but speeds run a wide range. Some terminals /CLM, HQM, OLM, BLI and BFI/ have seen gusts drop off significantly, if not entirely with speeds generally ranging 5-10 kts. SEA and PWT continue to see breezy conditions as speeds remain 12-16 kts with persisting gusts up to 20-25 kts. Winds at PAE continue to howl as speeds still remain 24-28 kts with gusts around 40 kts. Speeds are expected to diminish further overnight eventually reaching 8-12 kts with minimal gusts. However, speeds and gusts will get a boost from a secondary front Wednesday with 10-15 kts with gusts to 25 kt expected to kick in area-wide by late morning/early afternoon.

Cigs have generally improved to widespread VFR although some isolated spots under shows are seeing MVFR conditions emerge. Most terminals should remain VFR for the TAF period, although PWT, HQM and BLI may dip down into MVFR from time to time overnight. Widespread VFR conditions are expected Wednesday.

KSEA...VFR conditions in place and expected to remain so for the TAF period. Southwesterly winds 10-15kt with gusts to 25 kts this evening before easing slightly to 8-12 kts between 03-06Z. As stated above, wind speeds 10-15 kts with gusts to 25 kts are expected to return by 18Z and remain that way into the afternoon.

18

MARINE

A vigorous frontal system will sweep across across the waters this evening. Strong onshore flow will settle in behind the front through the strait. Gales remain in effect all waters with coastal seas in the double digits tonight and persisting into Wednesday. Surface ridging will begin to rebuild across the waters on Thursday and remain in place into Friday before another front approaches over the weekend. Seas will slowly subside to 6-8 feet Thursday and 5-7 feet toward the weekend.

HYDROLOGY

Flows on the Cedar River at Renton remain high due to dam operations and will rise above Minor Flood Stage later this afternoon. Elsewhere, river flooding is not expected over the next 7 days.

Mazurkiewicz

SEW WATCHES/WARNINGS/ADVISORIES

WA...Winter Weather Advisory until 5 AM PDT Thursday for Cascades of Snohomish and Northern King Counties-Cascades of Whatcom and Skagit Counties.

PZ...Small Craft Advisory until 5 AM PDT Wednesday for Grays Harbor Bar.

Gale Warning until 11 PM PDT this evening for Central U.S. Waters Strait Of Juan De Fuca-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-Puget Sound and Hood Canal-West Entrance U.S. Waters Strait Of Juan De Fuca.

Small Craft Advisory until 11 AM PDT Wednesday 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-West Entrance U.S. Waters Strait Of Juan De Fuca.

Gale Warning until 9 PM PDT this evening for Admiralty Inlet- East Entrance U.S. Waters Strait Of Juan De Fuca-Northern Inland Waters Including The San Juan Islands.

Small Craft Advisory until 5 AM PDT Wednesday for East Entrance U.S. Waters Strait Of Juan De Fuca-Northern Inland Waters Including The San Juan Islands.