773 FXUS66 KSEW 250408 AFDSEW Area Forecast Discussion National Weather Service Seattle WA 808 PM PST Fri Jan 24 2025 .SYNOPSIS...Offshore upper-level ridge building into Northern British Columbia over the weekend with the ridge moving directly over Western Washington Monday and Tuesday. Ridge shifting east Wednesday night with an organized front Thursday with and leading into Friday. && .SHORT TERM /TONIGHT THROUGH TUESDAY/...No major updates were made this evening as the forecast is still on track. Updates have been made to the aviation and marine sections, though the rest of the previous discussion can be found below with minor timing updates. An upper-ridge is positioned over the Gulf of Alaska and it won`t be in a hurry to progress. For tonight, dry and cold conditions are in the forecast as temps bottom mostly into the 20s. Rural areas away from water sources are likely to be the coldest as values fall into the lower 20s. Locations along the immediate coastline will be the warmest in the lower to mid 30s. Frosty surfaces and patchy fog/low clouds are favorable into Saturday morning as surface winds relax. Not much change expected in the short term forecast. Guidance agrees on the aforementioned ridge`s center just west of Haida Gwaii on Saturday before gently progressing. By monday, its axis will reside off the Washington coast as it cuts into Vancouver Island and the rest of BC. Dry and cold conditions are expected as widespread overnight lows in the 20s persist. A few isolated areas may flirt with Cold Weather Advisory criteria for Friday and Saturday night (Arlington, Enumclaw, etc.) but, it looks like we`ll remain just above criteria and as a result we have decided to off on issuing any products. .LONG TERM /WEDNESDAY THROUGH SATURDAY/...Deterministic guidance agree on the upper-ridge remaining in place Tuesday through Wednesday. However, changes are appearing more favorable for Thursday as the ridge pushes more eastward and inland. An organized front is slated to arrive by Thursday evening with the best chance for widespread precipitation we`ve seen in quite some time. Snow levels will be around 2500 to 3000 feet with the mountains getting a few inches of new snow. McMillian && .AVIATION...Northerly flow aloft continues over Western Washington with upper ridging poised offshore and an upper trough digging southward over the Northern Rockies. VFR will continue tonight into Saturday (only exception being a slight chance of patchy LIFR freezing fog restricted to the Southwest Interior and extreme south Puget Sound Saturday morning). Winds will remain light out of the north/northeast at 4 to 8 kt. KSEA...Mostly clear skies/VFR expected through the TAF forecast. Surface winds northerly 10 to 13 knots will ease to northeasterly 7 knots or less this evening through Saturday. 27/HPR && .MARINE...Surface ridging strengthens over interior British Columbia and east of the Cascades today into Saturday while a broad surface trough deepens well to the south over California. This will lead to northerly or weak offshore flow. This general pattern remains in place into early next week. The next front will approach the coastal waters around the middle of next week. 27 && .HYDROLOGY...No river flooding is expected in the next 7 days. && .SEW WATCHES/WARNINGS/ADVISORIES... WA...None. PZ...None. && $$
NWS SEW Office Area Forecast Discussion
