FXUS66 KSEW 060355 AFDSEW Area Forecast Discussion National Weather Service Seattle WA 855 PM PDT Mon May 5 2025 .SYNOPSIS... High pressure will lead to dry and warming conditions through Tuesday. A weak system will arrive by Wednesday bringing cooler temperatures and chances for showers. Somewhat warmer and generally dry conditions return late week before another front approaches the region over the weekend. && .SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/... Forecast remains on track this evening with just a few mid level clouds and otherwise a clear night for most. High pressure will remain in place into Tuesday, maintaining a warming trend for t with highs peaking into the mid 70s to around 80 across much of the region. By Tuesday night into Wednesday, the next trough will move into the region, ushering in cooler onshore flow and widespread but brief chances for showers. Any precipitation will wane Wednesday night. && .LONG TERM /THURSDAY THROUGH MONDAY/... Thursday into early Saturday will see a general transition from troughing to weak ridging across the area. This will allow conditions to dry and warm slightly, though no where near as warm as Tuesday. By later Saturday, confidence begins to diminish as an upper level trough approaches the region. At some point in the late Saturday-Sunday time frame this trough will spread precipitation east across the western Washington. Compared to yesterday, cluster analysis shows slightly better agreement in limited instability Sunday. That said, there is some indication that the trough could hang on a bit longer into early next week, keeping chances for showers going. -Wolcott- && .AVIATION... North/northwesterly flow aloft as high pressure builds over Western Washington. Currently VFR conditions across all terminals and expected to persist through the remainder of the TAF period. Northerly (westerly along the coast) surface winds are beginning to east this evening Winds will continue to ease overnight to 3 to 5 kt and shift northeasterly. North/northwesterly winds resume during the day Tuesday. KSEA...VFR conditions expected to persist through the remainder of the TAF period. N winds 5 to 10 kt easing to around 3 to 5 kt tonight and becoming more northeasterly. North/northwest winds resume again Tuesday. 29/62 && .MARINE... Surface high pressure building over the coastal waters will bring benign marine conditions through Tuesday. A weak frontal system will traverse the waters on Wednesday. Surface winds over the coastal waters will remain below 21 kt, however, a westerly push across the Strait of Juan de Fuca will lead to sustained winds speeds into the 21 to 30 kt range, with the strongest winds along the Central Strait. High pressure will rebuild over the region Thursday into Saturday, bringing calmer conditions over the waters. Seas generally between 5 to 6 ft will through Tuesday, and will rise to 7 to 8 ft on Wednesday. Conditions will ease on Thursday, with seas returning back to 5 to 6 ft through the weekend. 29 && .HYDROLOGY... The daily hydrology discussion has ended until the start of the next rainy season; it will only be updated if needed. && .SEW WATCHES/WARNINGS/ADVISORIES... WA...None. PZ...None. && $$