Area Forecast Discussion
Issued by NWS Seattle/Tacoma, WA
Issued by NWS Seattle/Tacoma, WA
708 FXUS66 KSEW 171616 AFDSEW Area Forecast Discussion National Weather Service Seattle WA 916 AM PDT Fri May 17 2024 .UPDATE...Drier conditions expected today as subtle ridging builds overhead. Lingering convergence zone activity over the central Cascades will gradually fizzle out as the day progresses. Temperatures are currently in the low 50s across the western WA lowlands and should top out in the low 60s for today`s high. The previous discussion is below along with an updated marine/aviation section. && .SYNOPSIS...Upper level troughing will continue to remain over western Washington through the weekend, keeping showery and cooler conditions around. A weak ridge looks to briefly build in the area for the start of next week, before troughing returns for more cool and showery conditions. && .SHORT TERM /TODAY THROUGH SUNDAY/...Recent radar imagery depicts a weakening convergence zone mainly focused over King/Snohomish county with some enhanced shower activity. This convergence zone will continue to weaken into the morning hours as upper level troughing remains over western Washington. Some lingering showers will be possible today but any hope for showers will likely be focused in the Cascades, with mostly dry conditions in the lowlands. Snow levels remain generally around 3000-3500 feet, with some light snow showers in the higher peak of the Cascades. Clouds may break up for some this afternoon, with high temps this afternoon remaining slightly below average in the low 60s. Another upper level low with a weak shortwave will then drift southward into Saturday with another round of showers throughout majority of the area, with high temps a bit cooler in the upper 50s. A brief but weak transient ridge will nudge into our area into Sunday evening for generally dry conditions in the interior and high temps in the lower 60s. .LONG TERM /MONDAY THROUGH THURSDAY/...Brief dry conditions will continue into Monday before another upper level low from British Columbia moves south into western Washington on Tuesday - with the return of unsettled weather. Showery and cool weather will continue yet again into the long term period with temperatures just slightly below normal. Mazurkiewicz && .AVIATION...Northwesterly flow will persist aloft today as an upper level trough over WA continues to push east and a ridge of high pressure remains situated over the NE Pacific. Post- frontal onshore flow will continue today and radar this morning shows some lingering showers pushing into the north and central Cascades. Showers will continue to diminish through the morning hours. Conditions mainly VFR this morning, with a few localized spots of MVFR. For MVFR areas, expect improvement towards VFR between 16-18Z and for VFR conditions to persist through much of the day. The low level air mass will remain moist, and with onshore flow continuing, expect to see another round of lower ceilings to develop overnight into Saturday morning. KSEA...Expect clouds at 2000 ft to scatter and for VFR conditions to persist through much of the day. Winds generally persisting from the S/SW at 10-14 kt. 14 && .MARINE...High pressure over the NE Pacific will maintain onshore flow across western WA through the weekend. Strongest winds will be over the Strait of Juan de Fuca with Small Craft Advisory winds extending through late tonight. The next frontal system will reach the region early next week. Seas hovering at 9-11 ft across the coastal waters this morning. Expect seas to continue to subside towards 7-9 ft this afternoon and to 5-7 ft over the weekend. 33/14 && .HYDROLOGY...The daily hydrology discussion has ended until the start of the next rainy season; it will only be updated as needed. && .SEW WATCHES/WARNINGS/ADVISORIES... WA...None. PZ...Small Craft Advisory until 11 AM PDT this morning for Admiralty Inlet-Coastal Waters From Cape Flattery To James Island 10 To 60 Nm-Coastal Waters From Cape Flattery To James Island Out 10 Nm-Coastal Waters From James Island To Point Grenville 10 To 60 Nm-Coastal Waters From James Island To Point Grenville Out 10 Nm-Coastal Waters From Point Grenville To Cape Shoalwater 10 To 60 Nm-Coastal Waters From Point Grenville To Cape Shoalwater Out 10 Nm-Northern Inland Waters Including The San Juan Islands-West Entrance U.S. Waters Strait Of Juan De Fuca. Small Craft Advisory until 5 AM PDT Saturday for Central U.S. Waters Strait Of Juan De Fuca-East Entrance U.S. Waters Strait Of Juan De Fuca. && $$