textproduct: Seattle/Tacoma

SYNOPSIS

Another frontal system will bring a return of rain and windy conditions later today into Sunday. A trend toward drier and cooler conditions is expected toward the middle portion of next week as the storm track shifts south of Western Washington.

SHORT TERM /TODAY THROUGH MONDAY/

An upper trough axis is moving onshore over Western Washington early this morning as another, more vigorous system approaches the region just offshore. A combination of high tide and low atmospheric pressure will bring a renewed threat of minor coastal flooding to the San Juans and Western Whatcom county this morning. Seas in excess of 20 feet continue along coast beaches. Rain and wind will increase along the coast later this afternoon with rain spreading inland this evening into the overnight hours. Windy conditions will also develop tonight near the east entrance to the strait and adjacent areas with some gusts of 45-55 mph.

The front will shift east of the Cascades by early Sunday afternoon with winds gradually easing and post-frontal showers across the area. A cooler air mass will follow the front...so there will be enough instability for isolated thunderstorms...especially near the coast. Snow levels will fall to around 4000 feet Sunday night, but QPF will be light by this time for just light accumulation at some of the higher passes. An upper level trough will remain over the area on Monday for scattered showers mainly coast and higher terrain and high temperatures back to around seasonal levels.

LONG TERM /MONDAY NIGHT THROUGH FRIDAY/

Drier conditions return to the area Monday night into Tuesday as the upper trough shifts eastward. Model solutions are falling into better agreement regarding the midweek system taking a further southward track and just brushing the southern portion of the CWA with some light precip on Wednesday. Ensembles favor cool and generally dry conditions to finish off next week with the potential for more active conditions returning thereafter.

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AVIATION

Southerly flow aloft this morning turning southwest later today as a frontal system pushes towards the region. Mostly VFR so far with areas of MVFR under heavier shower activity (coast and Olympic Peninsula). A vigorous front is slated to arrive this evening along the coast before spreading inland as the night progress. Shower activity will transition to steadier rainfall as a mix of VFR/MVFR conditions become more widespread. Southerly surface winds with gusts up to 25-30 kt across the entire area by late tonight. Winds will remain breezy into Sunday but less widespread. Areas of MVFR conditions will lead into Sunday morning as well.

KSEA...VFR conditions with vicinity showers throughout the day. The next front is slated to arrive tonight with steadier rainfall and gusty winds. Surface winds remain southerly, fluctuating between SE at times. Gusts up to 25 kt possible late tonight into early Sunday morning.

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MARINE

Numerous headlines remain in place as we're currently in between systems. SCA advisories are in effect this morning but as the day progresses, strong winds are slated to become more widespread as Gales become common across interior waters (minus Puget Sound but a SCA at the least may be needed) and Storm Force winds arrive for all of the coastal waters. The culprit is a sub 965 mb surface low swinging a cold front across the region this evening into the night hours. Along with winds, high seas are forecast around 20 ft today with a dominant period of 17 to 18 seconds, highly energetic. Seas will gradually decrease to 15 to 20 ft by Sunday morning. An additional increase to 20 to 25 appears likely in the afternoon. South winds will ease a bit on Sunday, but remain elevated especially for the Coastal Waters.

Winds subside further Monday into early Tuesday before increasing again going into midweek with a stronger weather system moving southwards well offshore. Confidence is leading towards developing high pressure for next weekend as benign conditions appear to be on the horizon.

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HYDROLOGY

The potential for flooding continues on the Skokomish River with periods of heavy rainfall through the weekend. A Flood Watch remains in effect.

River flooding is not expected on the other rivers in the area in the next 7 days at this time.

SEW WATCHES/WARNINGS/ADVISORIES

WA...Coastal Flood Advisory from 7 AM this morning to noon PST today for Lowlands of Western Whatcom County-San Juan County.

Wind Advisory from 4 PM this afternoon to 4 AM PST Sunday for Grays Harbor County Coast-Northern Washington Coast-San Juan County.

Flood Watch through late tonight for Olympia and Southern Puget Sound-Olympics-Southern Hood Canal.

High Surf Warning until noon PST today for Grays Harbor County Coast-Northern Washington Coast.

PZ...Small Craft Advisory until 10 AM PST Sunday for Grays Harbor Bar.

Small Craft Advisory until 4 PM PST this afternoon for Admiralty Inlet-East Entrance 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.

Gale Warning from 4 PM this afternoon to 4 AM PST Sunday for Central U.S. Waters Strait Of Juan De Fuca-West Entrance U.S. Waters Strait Of Juan De Fuca.

Gale Warning from 4 PM this afternoon to 7 AM PST Sunday 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 1 PM PST this afternoon 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.

Storm Warning from 2 PM this afternoon to 1 AM PST Sunday for Coastal Waters From Cape Flattery To James Island Out 10 Nm-Coastal Waters From James Island To Point Grenville Out 10 Nm-Coastal Waters From Point Grenville To Cape Shoalwater Out 10 Nm.

Storm Warning from 1 PM this afternoon to 1 AM PST Sunday for Coastal Waters From Cape Flattery To James Island 10 To 60 Nm-Coastal Waters From James Island To Point Grenville 10 To 60 Nm-Coastal Waters From Point Grenville To Cape Shoalwater 10 To 60 Nm.