Area Forecast Discussion
Issued by NWS Seattle/Tacoma, WA
Issued by NWS Seattle/Tacoma, WA
346 FXUS66 KSEW 231015 AFDSEW Area Forecast Discussion National Weather Service Seattle WA 315 AM PDT Sun Jun 23 2024 .SYNOPSIS...An upper level trough will produce clouds, cooler temperatures, and a few showers across Western Washington today. The trough will weaken tonight and a ridge of high pressure aloft will begin to rebuild into the area Monday. The ridge will strengthen as it shifts eastward on Tuesday for dry conditions and warmer temperatures. Another trough arrives Wednesday into Thursday for showers and cooler temperatures once again. A weak ridge late in the week will lead to drier conditions and near normal temperatures. && .SHORT TERM /TODAY THROUGH TUESDAY/...Clouds have filled in across most of Western Washington early this morning ahead of an upper trough moving into British Columbia. Spotty showers have already been observed across coastal areas and we should see some weak convergence zone activity develop across Skagit and Snohomish counties later this morning. QPF will be minimal...a few hundredths at best. High temperatures will be back below normal...in the 60s across most of the lowlands. The upper trough weakens tonight into Monday as it shifts eastward across interior British Columbia and this will allow upper ridging to begin rebuilding into the area. Most areas should see some sunshine return Monday afternoon with temperatures rebounding to near seasonal norms. Upper ridging gains amplitude as it shifts eastward into the northern Rockies later Tuesday. Interior temperatures will warm into the 70s while onshore flow keeps most of the coast firmly in the 60s. .LONG TERM /WEDNESDAY THROUGH SATURDAY/...Models remain consistent with an upper trough moving into the region Wednesday and Thursday. This one has a more southward trajectory than the current one and looks to provide much of the region with a decent chance at some measurable precip. And as one would expect, temperatures will cool back to below normal levels midweek. The upper trough shifts eastward into the Northern Rockies by the end of week allowing weak upper ridging to briefly rebuild. With continued onshore flow, temperatures will be held around seasonal levels...60s coast...70s inland. 27 && .AVIATION...Upper level trough over Western Washington today moving east tonight. Zonal flow aloft tonight and Monday. In the lower levels onshore flow through Monday. MVFR ceilings over most of the area this morning with the exception of the Central Puget Sound where ceilings are near 5000 feet. Ceilings in the Central Puget Sound lowering to MVFR 14z-16z. All areas ceilings lifting to low end of VFR 20z-23z with VFR ceilings continuing into Monday morning. KSEA...Ceilings near 5000 feet lowering to 2000 to 3000 feet 14z-16z. Ceilings lifting back up to near 4000 feet 20z-23z with VFR ceilings continuing into Monday morning. Southwest wind 8 to 12 knots easing after 03z. Felton && .MARINE...Weak high pressure will build back over the coastal waters and interact with lower pressure inland today through Tuesday. Another frontal system will reach the waters Wednesday. High pressure will rebuild over the coastal waters Thursday. Diurnal westerly pushes through the Strait of Juan de Fuca could result in small craft advisories for the Central and Eastern Strait Tuesday through Thursday in the evenings. Swell near 4 feet this morning building to 5 to 7 feet tonight into Monday. Felton && .SEW WATCHES/WARNINGS/ADVISORIES... WA...None. PZ...Small Craft Advisory until 5 AM PDT early this morning for Central U.S. Waters Strait Of Juan De Fuca-East Entrance U.S. Waters Strait Of Juan De Fuca. && $$