SHORT TERM /TONIGHT THROUGH SUNDAY/
Mid level clouds scattered over W WA this evening...otherwise fairly uneventful. Temperatures as of 7 PM PDT generally ranging from the upper 50s to lower 60s which is on track for overnight lows from inherited forecast.
Lingering low level moisture will likely allow for some low cloud development overnight.

No plans for an evening update as forecast looks to be on track. For additional forecast details, please refer to Previous Discussion section below.

18

From Previous Discussion...Cloudy skies with isolated shower activity south and east of the Puget Sound will persist today under northwest flow aloft. Onshore flow will cause cloudy skies to stick around, with periodic sun breaks in the afternoon. High temperatures today will stay on the cool side but will increase a degree or two from yesterday, peaking in the mid to upper 60s for much of the lowlands.

Flow will flatten overnight into Friday as weak ridging passes over the region. The next system will move into the Pacific Northwest later in the day, with a front and associated showers moving onto the coast by the late afternoon. Showers will overspread western Washington by late Friday evening with a surface front sliding across the area Saturday afternoon. The bulk of the moisture will be focused over the North Cascades, where weak instability will allow for locally heavier showers and may produce a few lightning strikes. Convergence zone showers are also favored to develop Saturday evening over and east of the Puget Sound while activity decreases elsewhere. Temperatures will remain below normal through the short-term in the mid 60s for most low elevations.

LONG TERM /MONDAY THROUGH THURSDAY/
From Previous Discussion...An upper level trough will dive south of the region on Sunday, maintaining cooler temperatures and generating more scattered shower activity across western Washington. Split flow will develop overhead by Monday as ridging amplifies from the west, allowing conditions to briefly dry out and warm up a few degrees. Uncertainty increases heading into next week, though ensembles continue to highlight another storm system moving into the region on Tuesday with another, potentially heavier, round of precipitation across western Washington. Cooler temperatures will also persist, remaining several degrees below normal for mid-September.

Lindeman

AVIATION
Northwesterly flow aloft will persist tonight with an upper level ridge over the region. Flow aloft will become more westerly through the day on Friday as the ridge flattens and a trough sinks down into the region from the north. Onshore flow will continue in the low levels through the period.

Widespread VFR conditions over the majority of W WA with MVFR conditions already present along the coast. Ceilings expected to lower area-wide overnight into Friday morning, with most terminals likely becoming MVFR with IFR conditions possible along the coast and those terminals that favor lower cigs. Conditions will improve and return to widespread VFR between 18-20Z Friday.

KSEA...VFR conditions in place this evening and early tonight.
Redevelopment of low stratus is expected by Friday morning, with probabilistic guidance showing a 45-50 percent chance of MVFR conditions developing at the terminal near 12Z. Winds are W/SW at 4- 8 kts and will become light again overnight. 14/18

MARINE
Surface high pressure will continue to build into the coastal waters tonight, with onshore flow expected to persist over the next several days. Westerly winds along the Strait of Juan de Fuca will increase to 10-20 kt this evening. Conditions in the Strait remain very much marginal when it comes to inherited SCA, however, still seeing occasional gusts at scattered sites within the advisory area as well as Race Rocks remaining just above criteria.
As such, will leave headline in place for now. Winds will diminish again late tonight through early Friday morning.

A weak system will sink southward and move into British Columbia Friday into the weekend. This will push a weak cold front through the area waters Friday night into Saturday. Increased onshore flow will persist in its wake, so may see another round of gusty westerly winds along the Strait Saturday night into Sunday. High pressure then looks to build back into the coastal waters early next week, before another system moves into the area waters on Tuesday.

Seas are generally hovering between 4-7 ft this evening and will continue to subside towards 3-5 ft again by the weekend. Seas then look to build back towards 5-8 ft again across the outer coastal waters by early next week. 14/18

SEW WATCHES/WARNINGS/ADVISORIES
WA...None.
PZ...Small Craft Advisory until 3 AM PDT Friday for Central U.S.
Waters Strait Of Juan De Fuca-East Entrance U.S. Waters Strait Of Juan De Fuca.