Area Forecast Discussion
Issued by NWS Seattle/Tacoma, WA
Issued by NWS Seattle/Tacoma, WA
315 FXUS66 KSEW 052316 AFDSEW Area Forecast Discussion National Weather Service Seattle WA 416 PM PDT Sat Sep 5 2026 .SYNOPSIS... Low pressure will bring showers and thunderstorms to western Washington this weekend, with warmer and drier conditions returning early next week. Offshore flow will lead to slightly warmer weather midweek. The next disturbance will bring a return of cooler conditions and shower chances later next week. && .SHORT TERM /TONIGHT THROUGH MONDAY NIGHT/... An upper low remaining over the region will continue to generate showers and thunderstorms across the region. The primary threats will continue to be brief downpours and lightning, though small hail and gusty outflow winds are also possible with the strongest storms that develop. Expect storms and showers to remain active through early this evening, with a gradual weakening as the sun goes down with the loss of daytime heating. The upper low continues to move over the region but begins to finally slide away on Sunday. With generally light flow aloft, this should keep showers more confined to the mountains. The chances will remain highest over the Cascades south of I-90, and there could be locally higher rainfall amounts with the slower moving storms. Expect showers to be mostly limited and generally dry conditions Monday for much of the area with the upper low finally pushing well inland and away from the region. Onshore flow increases at the low-level, bringing a steady push of marine clouds for the morning before some clearing in the late afternoon. && .LONG TERM /TUESDAY THROUGH SATURDAY/... Expect a shift to warmer and drier conditions toward midweek with the region remaining in between any significant weather disturbances. Light offshore flow in the lower levels will bring a slight warming back into the mid to upper 70s for mid- week, corresponding to minor (yellow) HeatRisk values. Another disturbance arrives later in the with a return of cooler temperatures and rain chances. && .AVIATION... Variable flow will continue as an upper level low continues to wobble over western Washington this afternoon. VFR conditions at all terminals this afternoon with generally light and variable winds across terminals. Shower and thunderstorm chances will exist once again, but should be confined to the Cascades, with largely no impacts to any terminals this evening. Winds will start taking a more N/NE direction this evening, but will continue to remain light. VFR conditions will continue to remain overnight, the exception being HQM, where brief low clouds may develop Sunday morning (09z-14z) with MVFR/IFR conditions. Elsewhere, VFR continuing into Sunday. KSEA...VFR at the terminal this afternoon continuing through the TAF period. Light and variable winds taking a more N/NE direction after 00z, remaining light. Light rain showers may impact the terminal this evening, but latest guidance shows most of these showers will be rather weak and will keep conditions at VFR. VFR will continue into Sunday with NE winds by the afternoon 3 to 6 knots. Mazurkiewicz && .MARINE... Broad low pressure remains over the area with showers and a few thunderstorms possible over the coastal waters this afternoon. Otherwise, marine seas and winds are benign and remaining under any advisory criteria. Northerly winds will continue over most of the area waters through the rest of this weekend and into early next week. Onshore flow looks to increase late Sunday into Monday, which could bring a push of westerlies down the Strait of Juan De Fuca for potential headlines. Coastal seas remaining generally around 3 to 6 feet through the rest of the weekend, with some locations in the outer coastal waters increasing to 6 to 7 feet on Monday. Seas will level back down to 3 to 5 feet through midweek. Mazurkiewicz && .SEW WATCHES/WARNINGS/ADVISORIES... WA...None. PZ...None. && $$