


Area Forecast Discussion
Issued by NWS Seattle/Tacoma, WA
Issued by NWS Seattle/Tacoma, WA
464 FXUS66 KSEW 170238 AFDSEW Area Forecast Discussion National Weather Service Seattle WA 738 PM PDT Thu Oct 16 2025 .SYNOPSIS...A weak frontal system will move across the area tonight into Friday bringing light rain showers to the area. A stronger, wetter system will follow Saturday evening into Sunday, bringing gusty winds, lowland rain, and mountain snow to the area. A brief drying trend is expected on Monday, before unsettled conditions look to return Tuesday and continue through the rest of the week. && .SHORT TERM /TONIGHT THROUGH SUNDAY/...The current forecast remains on track with no planned updates tonight. 33 Previous discussion...Recent satellite imagery shows mid to high level clouds streaming in ahead of an approaching system. This system is fairly weak and will spread light rain showers across the area, with showers moving in throughout the evening. QPF is pretty minimal so most areas may not even see rain, with only a few hundredths of an inch rain likely across the lowlands, which a quarter to a half an inch expected for the mountains. Increasing onshore flow into Friday will help develop a weak convergence zone across the Central and South Sound early Friday morning with showers tapering off by the afternoon for most of the area. High temperatures on Friday look to remain in the upper 50s to low 60s. A stronger and wetter system will cross over the region Saturday evening into Sunday, with widespread rain, breezy conditions, and mountain snow. Snow levels will rise upwards to 7000-9500 feet late Saturday evening as widespread rain will spread across most of the region. Winds will also become breezy, with gusts up to 20 to 30 mph at times throughout the overnight period. Winds will continue to remain breezy Sunday morning with showers continuing across most of the area - with areas along the Olympics and Cascades getting the bulk of the precipitation. Snow levels will fall back down towards 4500 feet in the wake of the front on Sunday, likely bringing some snow to the higher elevations of the mountains. The weekend system will bring QPF totals somewhere around a half an inch to an inch of rain across the interior lowlands, along with 1-3 inches along the coast and 2-4 inches for the Olympic and the Cascades. Though this event will be a good primer for area rivers, the antecedent dry conditions lend little concern for any flooding at this time. .LONG TERM /MONDAY THROUGH THURSDAY/...A transient upper ridge looks to move over the area on Monday which will help dry conditions out, with temperatures in the mid to upper 50s. Low confidence in the forecast starting on Tuesday as ensemble clusters still show a wide spread of solutions. A few weak systems look to move across the area midweek which would allow for showery and unsettled conditions. Will need to keep and eye on the intensity and exact placement of a ridge which could keep these systems away from western Washington, but for now, looks like unsettled conditions will continue at the end of the long term. Mazurkiewicz && .AVIATION...Flow aloft turning northwesterly this evening and remaining that way throughout Friday. Surface winds are generally light and variable at most terminals, however those that are seeing speeds generally 4-8 kts are seeing a prevailing direction from the south to southwest. Southerly winds expected to increase overnight for SEA, BFI, PAE and OLM to 5-10 kts by 12Z with all terminals reaching this direction and speed range by 19Z. A mix of MVFR to VFR conditions over W WA this evening as cigs continue to lower in advance of a weak system expected to pass through overnight. At the time of this writing, VFR conditions observed along the east side of the Sound and along the shores of the Strait with MVFR conditions elsewhere. Widespread MVFR conditions expected to accompany said system, with IFR/LIFR conditions at terminals more prone to lower cigs such as OLM, PWT and HQM...being in place by 12Z early Friday morning. Cigs expected to lift back into VFR conditions Friday afternoon, although timing may be difficult to pin down depending how much moisture is able to move over the area. Models seem to be leaning toward a 19-21Z time frame for area terminals to return to VFR cigs. KSEA...MVFR to VFR conditions this evening, as latest /02Z/ observation had cigs just under VFR threshold at 2800 ft. There may still be a little wiggle room to that before 06Z, but will start to see MVFR conditions emerge more persistently by 10Z, bottoming out around 1500 ft by 12Z. Recovery to VFR expected by 19Z, with additional lifting/clearing throughout the remainder of the afternoon. 18 && .MARINE...A weak frontal system will cross area waters tonight into early Friday with weak high pressure building in thereafter through Saturday morning. Post-frontal winds will increase through the Central Strait of Juan de Fuca on Friday, reaching Small Craft Advisory strength. A much stronger frontal system will move over area waters Saturday into Sunday, with numerous headlines expected across the outer and inner waters over the weekend. A series of additional frontal systems will cross the region through next week. Seas generally 4 to 6 feet will gradually build to 5 to 7 feet through Friday morning, then increase to 9 to 12 feet by Friday evening. Seas will remain elevated through the weekend, building as high as 19 feet across the outermost outer waters and 15 feet along the coastal waters on Sunday. Seas may be steep at times, especially Saturday night into Sunday. Seas are expected to fall below 10 feet briefly on Monday before building back to 10 to 16 feet through the remainder of the week. 15 && .SEW WATCHES/WARNINGS/ADVISORIES... WA...None. PZ...Small Craft Advisory from 5 AM to 5 PM PDT Friday for Central U.S. Waters Strait Of Juan De Fuca. && $$