textproduct: Seattle/Tacoma

SYNOPSIS

A series of frontal systems will bring a return of widespread rain and occasionally windy conditions today through the weekend. A trend toward drier and cooler conditions are expected toward the middle portion of next week as the storm track shifts south of Western Washington.

SHORT TERM /TODAY THROUGH SUNDAY/

Based on area tide gauges, we're seeing minor to moderate coastal flooding with high tide this morning. Pressure is a little higher on Saturday but will evaluate if more headlines are needed. 33

Previous discussion...Rain is spreading onto the coast this morning ahead of the first of a couple frontal systems that will impact the region in the days ahead. Along with the rain, breezy to locally windy conditions will develop along the coast, the North Interior, and near the Cascade gaps. A combination of high tide and lower atmospheric pressure will contribute to minor to moderate coastal flooding today as well. Larger seas building to around 20 feet will reach the coast where a high surf advisory remains in effect. Rain will turn to showers by tonight as an upper trough axis shifts onshore.

A second and stronger frontal system will move into the area later Saturday into Saturday night. QPF remains in the same ballpark as previous estimates with around 1.5 to 2 inches for much of the coast, 3+ inches on the south facing slopes of the Olympics, and somewhere between 0.50 and 1 inch for much of the interior lowlands. NBM probabilities of wind gusts exceeding 50 mph along portions of the coast are around 60 to 80 percent for Saturday afternoon/evening with another bullseye of 50 to 60 percent probabilities near the east entrance to the strait later Saturday night. Elsewhere, peak wind gusts Saturday night will be roughly 30 to 40 mph. Post-frontal showers continue into Sunday with winds easing.

LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/

An upper trough will move into the area Sunday night and Monday and introduce a notably cooler air mass from what we've seen recently. QPF will be light by this time, but snow levels will dip to around 4000 feet. Models are continuing the trend of the next system toward the middle of next week taking a more southern track and just clipping the far southern portion of the CWA. Beyond that, upper ridging is on track to bring a period of drier weather to round out the remainder of the week. And this time of year, that probably means some fog and cool temperatures.

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AVIATION

South flow aloft continues into tonight as a frontal system moves across western Washington. Steadier light rain progresses eastwards across Puget Sound through the afternoon. Predominantly VFR cigs through this afternoon with brief MVFR conditions at times, mainly for the Olympic Peninsula. Isolated showers develop after the front tonight. VFR favored for most locations tonight into Saturday AM with areas of MVFR at times for the Olympic Peninsula and coast. Surface winds generally remain south-southeast through the period, with localized gusts to 25 kt along the coast.

KSEA...VFR conditions with light rain through approximately 00z, with a few rain showers lingering tonight into Saturday AM. Cigs through the afternoon ranging 050-090. Mainly low-end VFR cigs Saturday AM, with a 25-30% chance of MVFR cigs from 09z-15z. S/SW surface winds fluctuating between 4 to 10 kts. JD

MARINE

SCAs will remain for the East Strait, Admiralty Inlet and Grays Harbor Bar well into tonight. A SCA has been issued for the West Strait as well for the remainder of the morning before dropping off this afternoon due to ESE winds reaching criteria. Gales gusts are firmly in place across the coastal waters as an occasional storm force gust cannot be ruled out, particularly over the outer coastal waters. SCA winds look to potentially pick up later tonight into Saturday morning for the Northern Inland waters

Winds over the inner waters will remain elevated into Saturday morning, winds over the coastal waters will briefly decrease as gales transition to more Small Craft strength. However, the next frontal system is set to arrive late Saturday afternoon as a sub 970 mb low generates very strong southerly winds. REFS probabilities are now showing greater than 90% chance of Storm Force gusts being met over the outer and inner coastal waters while the NBM is showing 50- 60% into Saturday night. For this reason a Storm Force Watch has been issued for the Coastal Waters, with additional Gale Watches issued for portions of the interior waters. Small Craft winds are favored to continue on Sunday, at least over the coastal waters and portions of the inland waters Conditions are favored to calm by Monday, with potential for continued windy conditions over the waters returning by Tuesday.

Today's system will bring very large seas to the Washington coast, with high confidence in waves building to 20-26 ft over the coastal waters by this afternoon. These large waves will also be very energetic, with a dominant period of 18 to 20 seconds. Seas will remain elevated through Saturday morning and will briefly ease a bit into early Sunday, remaining between 14 to 18 feet. Another system will send another round of large, long period waves on Sunday with another round of waves likely 20-22 ft or higher through Monday morning. Seas look to ease a bit after Monday, but will likely stay in the 12-15 foot range heading into the middle of next week.

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HYDROLOGY

The potential for flooding continues on the Skokomish River with periods of heavy rainfall Friday 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 Warning until noon PST today for San Juan County.

Coastal Flood Advisory until noon PST today for City of Seattle-Downtown Everett / Marysville Area-Eastern Kitsap County-Island County-Lowlands of Pierce and Southern King Counties-Lowlands of Western Skagit and Northwestern Snohomish Counties-Lowlands of Western Whatcom County- Northern Hood Canal-Olympia and Southern Puget Sound- Shoreline / Lynnwood / South Everett Area-Southern Hood Canal.

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

High Surf Advisory from noon today to 7 AM PST Saturday for Grays Harbor County Coast-Northern Washington Coast.

Coastal Flood Advisory until 5 PM PST this afternoon for Grays Harbor County Coast.

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

Small Craft Advisory until 4 PM PST Saturday for West Entrance U.S. Waters Strait Of Juan De Fuca.

Small Craft Advisory until 4 PM PST Saturday for Admiralty Inlet-East Entrance U.S. Waters Strait Of Juan De Fuca.

Gale Watch from Saturday afternoon through Sunday morning 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 4 PM this afternoon to 4 PM PST Saturday for Northern Inland Waters Including The San Juan Islands.

Gale Warning until 10 PM PST this evening 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 10 PM this evening to 1 PM PST Saturday 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 Watch from Saturday afternoon through late Saturday night 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.