textproduct: Seattle/Tacoma

SYNOPSIS

An upper level ridge will remain over western Washington through Thursday. Onshore flow will continue throughout the week and will push additional rounds of morning marine stratus into the area the next few days. A dissipating frontal system will then move into the region on Friday, bringing the next chance of shower activity mainly to the coast and mountains. High pressure then looks to rebuild into the region over the weekend and remain situated across the area into early next week.

SHORT TERM /TODAY THROUGH FRIDAY/

Cloudy start with onshore flow keeping the stratus in place over Western Washington this morning. Much like yesterday, temperatures could end up a bit cooler as a result of the lingering stratus, so expect highs to only top out in the mid 60s to low 70s across the interior today. Latest HREF probabilistic guidance only suggests about a 10-20 percent chance of temperatures exceeding 70 for the interior areas in and around the Seattle metro. The coast will stay cooler under the influence of the marine layer and looks to see afternoon temperatures top out in the upper 50s to low 60s.

High pressure will remain in place over the area into Thursday. Expect another round of stratus to push into the interior on Thursday morning and for afternoon highs to generally be in the upper 60s to low 70s across the interior and upper 50s to low 60s for areas along the coast.

A weak, dissipating frontal system will then approach the area on Friday as the ridge axis pushes inland. While the majority of the area looks to remain dry, this system will bring back a small chance for some shower activity mainly for areas along the coast and in the mountains. Any rain that does fall looks to remain light, with latest probabilities suggesting less than a 15 percent chance of more than a tenth of an inch of rain falling across the interior lowlands. The more notable impact from this system will be the increased cloudiness and slightly cooler temperatures, with most spots expected to only see highs reach the upper 50s to mid 60s.

LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/

Ensemble clusters remain in good agreement that high pressure will build back into the Pacific Northwest over the weekend and remain situated over the area into early next week. Meanwhile, deterministic guidance favors a weaker ridge, and brings some additional rounds of light precipitation to the northern tier of western Washington as systems pass to the north. Overall, expect mostly dry conditions to continue across the area and for temperatures to warm back up to above normal by early next week. More widespread Minor HeatRisk will return, with highs currently expected to be in the mid to upper 70s across the interior lowlands and mid to upper 60s along the coast.

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AVIATION

High pressure over the region today with low level onshore flow. Western WA lowlands remained covered under marine clouds that have pushed into the Cascade valleys. Ceilings are mainly in IFR range this morning. The trend is for a gradual lift into MVFR conditions this morning with possible VFR conditions after 21z. Does not appear that will will totally break out today given the satellite imagery. Clouds will lower again overnight for IFR to MVFR conditions once again.

KSEA...IFR to MVFR conditions this morning with a slow/gradual lift of ceilings (but not completely sct or clear). Low-end VFR possible after 21Z. A return to MVFR conditions expected overnight. S/SW wind to 10 kt. 33

MARINE

Surface high pressure will continue to remain offshore for the next couple of days with onshore flow continuing. Latest guidance has shown decreased probabilities of gale gusts over the Central and Eastern Strait of Juan De Fuca for this afternoon's push down the Strait as a weak system passes by. Have replaced the Gale Watch with a Small Craft Advisory with more agreement that the wind strength will be less than originally anticipated. A gust or two up to gale strength cannot be ruled out though. Have also issued a Small Craft advisory for all of the coastal water zones as seas start to build towards 9 to 11 feet later this evening, lasting into Thursday - with some gusts up to 25 kts at times.

Mazurkiewicz

HYDROLOGY

The daily hydrology discussion has ended until the start of the next rainy season; it will only be updated during this time as needed.

SEW WATCHES/WARNINGS/ADVISORIES

WA...None. PZ...Small Craft Advisory until 5 AM PDT Thursday for Central U.S. Waters Strait Of Juan De Fuca-East Entrance U.S. Waters Strait Of Juan De Fuca.

Small Craft Advisory from 2 PM this afternoon to 5 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.