textproduct: Seattle/Tacoma

SYNOPSIS

Dry and cooler conditions today as a colder air mass settles over the region. A dry pattern will persist into the week, with a gradual warming trend peaking on Friday. Unsettled conditions return this weekend.

SHORT TERM /TODAY THROUGH THURSDAY/

An upper level low moving across Western Canada continues to bring onshore flow across Western Washington. A dry cold front associated with the upper level low has moved through, allowing a colder air mass to situate over the region. High temperatures today will be in the 50s.

Temperatures tonight into Wednesday morning are expected to get chilly, with low temperatures dipping into 30s. Cooler overnight temperatures near freezing, may promote the development of frost across portions of Western Washington that may impact sensitive vegetation. Highest confidence (70-90% chance) for frost is for the southern interior, for which a Frost Advisory has been issued to start late tonight.

A gradual warm up is expected to start on Wednesday and continue late in the week as weak high pressure builds over Western Washington. High temperatures will be in the mid 50s for the coast and low 60s on Wednesday. By Thursday expect low 60s along the coast and mid to upper 60s along the interior. Low temperatures on Thursday morning will be in the mid to upper 30s and Friday morning will be in the low 40s .

LONG TERM /THURSDAY NIGHT THROUGH MONDAY/

Dry conditions continue through Friday. Unsettled conditions expected to return this weekend, as an upper level low moves south from the Gulf of Alaska. However, there is uncertainty regarding the track of the low. Some solutions favor the center of the low to move into California, resulting in wet but slightly drier conditions for Western Washington. Other models favor the low to move over Oregon, resulting in a wetter solution for the region through Monday.

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AVIATION

Westerly flow aloft becoming more northwesterly into Tuesday. Onshore flow present as the lower levels early this morning as MVFR and isolated IFR cigs develop in portions of Puget Sound. Confidence in cigs at or below 3000 ft is around 40-60% through 16-18Z, with more widespread scattering and VFR thereafter. Breezier NW winds through the Strait of Georgia could also impact BLI late this morning and into early afternoon. Interior terminals are expected to transition from WSW flow to NNW flow this afternoon, occuring first at northern terminals and progressing south between 21Z-00Z.

KSEA...MVFR cigs have made it to the terminal early this morning with southwesterly surface flow. Expect the MVFR cigs to persist through 12-14Z, becoming closer to low end VFR by the late morning. More widespread scattering likely after 00Z. Winds will transition to NW at 5-7 kts after 00Z, becoming NNE throughout the rest of the valid TAF period.

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MARINE

All marine headlines have been retained as onshore winds continue today, with high pressure building on the back end of a passing front. Gales in the Strait of Juan de Fuca are still forecast to end later this morning. Seas are still elevated, particularly in the northernmost outer coastal zone up to 15 feet, subsiding to 10 feet or less by 18Z this morning. Winds will slowly ease throughout the rest of the day and remain relatively light through the rest of the week as high pressure remains in place over the northeast Pacific.

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HYDROLOGY

No river flooding expected in the next 7 days.

SEW WATCHES/WARNINGS/ADVISORIES

WA...Frost Advisory from 11 PM this evening to 9 AM PDT Wednesday for Foothills and Valleys of Thurston and Lewis Counties- Lowlands of Lewis and Southern Thurston Counties-Middle Chehalis River Valley-Olympia and Southern Puget Sound- Willapa and Black Hills.

PZ...Small Craft Advisory until 2 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-West Entrance U.S. Waters Strait Of Juan De Fuca.

Gale Warning until 5 AM PDT early this morning for Central U.S. Waters Strait Of Juan De Fuca-East Entrance U.S. Waters Strait Of Juan De Fuca.

Small Craft Advisory until 9 AM PDT this morning for Northern Inland Waters Including The San Juan Islands.

Small Craft Advisory until 5 AM PDT early this morning for Admiralty Inlet.