textproduct: Seattle/Tacoma

SYNOPSIS

A vigorous early season storm system moving through the area this afternoon and evening will bring gusty winds, rain and even isolated thunderstorms for some areas. The overall weather pattern will remain cool and unsettled through the weekend with possible drying and warming following early next week.

SHORT TERM /TONIGHT THROUGH FRIDAY NIGHT/

Rain has moved onshore through the late morning, and into the central Puget Sound as of early afternoon. Progression of the system has been a bit slower, but overall forecast remains on track, with rain spreading through the interior through the afternoon and evening. In addition to the rainfall, there remains a 15-20% chance of isolated thunderstorms this afternoon and evening - particularly along the coast and Olympic Peninsula. Southerly winds along the coast will continue to pick up over the interior through the afternoon into the early evening. Strongest winds over the interior - especially in the Admiralty Inlet area, San Juan Islands, Western Whatcom and Skagit Counties and even along the I-5 corridor south of Olympia could see gusts to 40 or 45 mph. Impacts associated with gusty winds may occur at lower wind speeds due to Summer foliage on trees. Steady rain will change to showers behind the front this evening, with winds easing along the coast early evening and over the interior before midnight.

The associated upper level low will linger over the region Thursday and Friday - keeping the overall pattern relatively cool and unstable - with showers and 15 to 25% chance of afternoon and evening thunderstorms especially over the mountains.

LONG TERM /SATURDAY THROUGH WEDNESDAY/

Ensemble-based clustering systems continue to emphasize the likelihood of the upper level low/trough remaining over the Pacific Northwest through the weekend. Differences in the forecast remain largely limited to differences with embedded features or whether or not the upper level low opens up and lingers as a trough (17% of the members) or lingers as a more consolidated upper level low (83% of the members). Ultimately this equates to a high degree of confidence in the cooler unsettled pattern lingering through the weekend, with showers and potentially potential isolated thunderstorms especially over the mountains. Ensemble clusters show the pattern opening up early in the week, allowing the upper level system to shift eastward with much of the variability in how progressively this occurs. 15% of the members falling into a more progressive or faster scenarios at day 6 (Monday), and the bulk of the remaining members pushing the change into Tuesday. The overall message remains for a transition to drier and relatively warmer conditions early next week.

AVIATION

South to southwest flow aloft into Thursday an an upper low digs southwards along the Washington coast. A front continues to move across the area this afternoon with rain spreading across Puget Sound. The bulk of the stratiform rain moves out of W WA by this evening. A few rain showers will then exist along Olympic Peninsula tonight, with a 20% probability for thunderstorms along the southern WA coast. VFR cigs for most areas into tonight with MVFR along the coast and in areas of heavier rain. Cigs may slowly lower towards higher end MVFR for localized Puget Sound terminals Thursday AM. Breezy south winds through this afternoon. Gusts will be strongest along the coast and north of PAE with the exception being CLM. Winds will slowly ease tonight.

KSEA...VFR conditions are expected to continue into tonight. A front is moving through this afternoon with the majority of steadier rain ending around 01z. A few showers will linger later tonight into Thursday. Cigs slowly lower towards low-end VFR and high-end MVFR Thursday morning, with a 30-35% chance of MVFR cigs between 13 to 18z Thursday. Breezy south winds this afternoon, peaking through 01z. Wind gusts of 20 to 25 kts are expected during this period. South winds continue into Thursday. JD

MARINE

A frontal system continues to move across Western Washington this afternoon for increased southerly winds. Gale force wind gusts over the Coastal Waters will taper off this evening, with gales continuing into this evening for the eastern Strait of Juan de Fuca, Admiralty Inlet, and northern inland waters. Southerly winds will taper off tonight, but remain breezy in these aforementioned areas, as such, a Small Craft Advisory continues tonight. Otherwise, light winds are expected late Thursday through Friday with broad low pressure over the region. Northerly winds develop Saturday and continue into early next week.

Rain showers linger tonight through Thursday. There is a 20 to 30% chance for thunderstorms along the Coastal Waters tonight, with a 10 to 25% chance of thunderstorms for all waters Thursday afternoon.

Seas ranging 8 to 14 feet today. Seas remain in the 8 to 11 foot range tonight through Thursday morning. Seas further ease to 4 to 6 feet late Thursday through the weekend. JD

SEW WATCHES/WARNINGS/ADVISORIES

WA...Wind Advisory until 8 PM PDT this evening for Island County- Lowlands of Western Skagit and Northwestern Snohomish Counties-Lowlands of Western Whatcom County-Port Townsend Area-San Juan County.

Wind Advisory until 5 PM PDT this afternoon for Grays Harbor County Coast-Lowlands of Lewis and Southern Thurston Counties-Northern Washington Coast.

PZ...Small Craft Advisory until 5 PM PDT this afternoon for Grays Harbor Bar.

Gale Warning until 11 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 from 11 PM this evening to 11 AM PDT Thursday 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 11 PM PDT this evening for Puget Sound and Hood Canal.

Gale Warning until 5 PM PDT 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.

Small Craft Advisory from 5 PM this afternoon to 11 AM PDT 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.