textproduct: Seattle/Tacoma

SYNOPSIS

A frontal system moves across the area late today into Sunday for steadier rain, gusty winds. Post-frontal showers on Sunday. Unsettled conditions continue Monday with troughing over the western US. Another low approaches the west coast midweek with the majority of the precipitation focused south of western Washington.

SHORT TERM /TONIGHT THROUGH MONDAY NIGHT/

Increasing clouds this afternoon with localized showers ahead of the next frontal system approaching the region from offshore. Steadier rain moves onshore late this afternoon into this evening, moving into Puget Sound tonight. Steadier precipitation then slides into the Cascades by Sunday morning. South winds also increase with this front, with the strongest winds along the coast and San Juan Islands. A Wind Advisory remains in effect for these areas with gusts of 50 to 55 MPH. A Wind Advisory has also been issued for Whidbey Island and Admiralty Inlet region with southeast wind gusts of 40 to 50 MPH. Elsewhere, breezy conditions are expected, mainly ranging 25 to 40 MPH. Post-frontal showers develop on Sunday, resulting in unsettled conditions at times. In addition, weak instablilty (150-300 J/kg) may lead to localized thunderstorms, particularly along the coast and Olympic Peninsula. Otherwise, winds remain elevated on Sunday, but slowly ease during the afternoon hours. A Coastal Flood Advisory has been issued for the San Juan Islands again Sunday morning before tides gradually decrease through this week.

Upper troughing over the western US on Monday will keep a limited threat for showers over the area, especially for the Olympic Peninsula and Cascades. Highs in the mid to upper 50s through Sunday will cool on Monday to the low 50s.

LONG TERM /TUESDAY THROUGH SATURDAY/

Drier conditions are expected on Tuesday as troughing moves into the interior Rockies. A deep surface low approaches the west coast on Wednesday. Ensembles keep the majority of the precipitation focused south of western Washington with this system, however a chance of precipitation remains due to some lingering uncertainty in the proximity of the system. The system moves onshore across CA on Thursday, allowing for another period of drier conditions late week. Uncertainty increases further in ensembles by next weekend, but indications of troughing offshore may result in the return of a more active pattern. JD

AVIATION

A mix of MVFR and VFR conditions this afternoon with some areas of low clouds associated with scattered showers across portions of the area, as well as increasing mid and high level clouds as a frontal system approaches the coast. Low-end VFR conditions should prevail for most through this evening before rain begins to arrive to the coast this evening and will move through the interior overnight. A brief period of MVFR cigs (and vis along the coast in heavier rain) will be possible overnight, otherwise ceilings look to remain VFR (in the 3500-4500 ft range) through much of Sunday as scattered showers continue. There is a low (15-20%) chance of isolated thunderstorms, mainly along the coast.

South/southeasterly winds 8-15 kt with gusts to 25 kt will increase tonight, with gusts up to 25-30 kt across the entire area by late tonight. Locally higher gusts 30-40 kt possible along the coast and through the northern interior overnight. Winds will peak overnight but remain elevated through much of Sunday with continued gusts of 15-25 kt as winds will be very slow to decrease.

KSEA...VFR conditions with vicinity showers through this afternoon. The next front is slated to arrive tonight with steadier rainfall and the potential for a brief period of MVFR cigs overnight between around 09-15Z Mon. Surface winds remain S/SE. Winds 8-12 kt today, increasing to 10 to 15 kt overnight with gusts up to 25 kt possible through early Sunday. Winds will begin to slowly ease Sunday afternoon with VFR conditions continuing.

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MARINE

A strong low pressure system will send a cold front across the area waters as the low center tracks to the northeast along the British Columbia coast. Winds will continue to increase across the area, with winds peaking overnight. Storm Warnings remain in effect for the coastal waters with peak wind gusts overnight forecast up to 40- 50 kt, particularly across the offshore coastal waters. Gale Warnings remain in effect across the most of the interior waters, with a Small Craft Advisory in effect for the Puget Sound. Winds will begin to decrease Sunday morning but will do so gradually, with most locations seeing Small Craft Advisory level winds through much of the day on Sunday. Winds will finally ease over the coastal waters and northern Salish Sea Sunday night.

Seas are slowly easing from their maximum last night, but will remain in the 16-20 ft range before the strong winds overnight raise seas back to around 20-22 ft. These short period waves will ease fairly quickly early Sunday morning to around 15-18 ft before the westerly long-period swell arrives late Sunday morning, with waves peaking in the afternoon/evening hours. Seas will rise to a maximum of around 20-22 ft at around 16 seconds, but could be as high as 25 ft farther offshore.

With higher pressure building across the area on Monday, this will allow for a break in the activity, with winds remaining light and allowing for waves to decrease throughout the day, lowering to around 10-12 ft by early Tuesday.

A low pressure system will form over the open northeast Pacific and move off to the southeast of Washington Tuesday into Wednesday, making landfall over northern California late Wednesday. While somewhat distant, this system will allow winds to turn offshore and increase, as well as increasing waves for the next round of headlines mid-week. Calmer conditions under high pressure are then favored Thursday into the end of the week.

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HYDROLOGY

The potential for flooding continues on the Skokomish River with another round of steadier rainfall tonight into early Sunday. 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...Wind Advisory until 4 AM PST Sunday for Grays Harbor County Coast-Northern Washington Coast-San Juan County.

Coastal Flood Advisory from 8 AM to noon PST Sunday for Lowlands of Western Whatcom County-San Juan County.

Flood Watch through Sunday morning for Olympia and Southern Puget Sound-Olympics-Southern Hood Canal.

Wind Advisory until 7 AM PST Sunday for Island County-Port Townsend Area.

High Surf Advisory until 10 AM PST Sunday for Grays Harbor County Coast-Northern Washington Coast.

High Surf Warning from 10 AM Sunday to 10 AM PST Monday for Grays Harbor County Coast-Northern Washington Coast.

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

Gale Warning until 4 AM PST Sunday for Central U.S. Waters Strait Of Juan De Fuca-West Entrance U.S. Waters Strait Of Juan De Fuca.

Small Craft Advisory from 4 AM to 10 PM PST Sunday for West Entrance U.S. Waters Strait Of Juan De Fuca.

Gale Warning until 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 from 7 AM to 10 PM 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 Sunday for Puget Sound and Hood Canal.

Storm Warning until 1 AM PST Sunday 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.

Small Craft Advisory from 1 AM to 10 PM PST Sunday 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.