Area Forecast Discussion
Issued by NWS Seattle/Tacoma, WA
Issued by NWS Seattle/Tacoma, WA
364 FXUS66 KSEW 040320 AFDSEW Area Forecast Discussion National Weather Service Seattle WA 820 PM PDT Thu Sep 3 2026 .SYNOPSIS...A low pressure system will remain situated over the Pacific Northwest through the weekend, maintaining cooler temperatures and daily chances for light showers and isolated thunderstorms. Split flow is favored to develop early next week, bringing drier and slightly warmer conditions. Chances for additional rain increase towards the end of next week with the potential arrival of another trough. && .SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/...A low pressure system that brought fall-like conditions to western Washington will continue to influence the weather into the weekend, bringing daily chances for scattered showers and isolated thunderstorms. The storm system will continue to drift southwards into tonight, with showers slowly dissipating overnight. Showers will then further develop over the Cascades and southern interior again midday Friday, drifting northwestward. By Saturday, the low shifts northward, advecting wrap-around moisture into the area, bringing more widespread chances for showers and isolated thunderstorms. Temperatures through the short-term will remain below normal, with highs in the upper 60s to low 70s each day. && .LONG TERM /SUNDAY THROUGH THURSDAY/...Forecast confidence decreases into next week, with some models keeping the low pressure system over us into Monday while some bring weak ridging over the area. While coverage decreases Sunday and especially into Monday, continued shower and thunderstorm activity remains possible alongside cooler temperatures. Models come into better agreement by Tuesday with split flow developing aloft, which would allow conditions to warm up and dry out with morning fog and low stratus. However, uncertainty remains over how long that would last, with another wet weather system on track to enter the region by next weekend. 15 && .AVIATION...Flow aloft becoming variable with upper-low offshore. Mostly VFR conditions this evening with some localized spots of MVFR ceilings due to lingering scattered showers. Overall, widespread VFR should continue throughout the evening, can could see brief MVFR at times in shower activity. Surface winds becoming variable and will lessen in speeds overnight. VFR will continue into Friday morning, with some guidance suggesting a 20-40% chance of low cloud/fog development across lower prone terminals. KSEA...VFR conditions this evening with scattered showers gradually decreasing. Surface winds becoming more variable and light overnight. Will likely see a return to southerly winds by Friday morning. MVFR patchy fog may develop around the terminal early Fri morning (20-30%) for a brief moment, but otherwise, VFR will continue. Mazurkiewicz/41 && .MARINE...No current advisories across the waters with winds and seas continuing to gradually subside. Seas remain around 8 to 9 ft this evening over the coastal waters, but will gradually decay through Friday. Broad low pressure remains in place, with showers and a few thunderstorms remaining possible, which could bring isolated gusty outflow winds. Otherwise, northerly winds develop over the waters Saturday through the start of next week. A marginal westerly push through the Strait of Juan de Fuca around Monday looks to be the next potential period of advisory strength conditions. Seas over the coastal waters subside further Saturday and remain in the 3 to 5 ft range through the first half of next week. && .SEW WATCHES/WARNINGS/ADVISORIES... WA...None. PZ...None. && $$