


Area Forecast Discussion
Issued by NWS Seattle/Tacoma, WA
Issued by NWS Seattle/Tacoma, WA
623 FXUS66 KSEW 161455 AFDSEW Area Forecast Discussion National Weather Service Seattle WA 755 AM PDT Thu Oct 16 2025 .UPDATE...Areas of patchy fog and low stratus will continue to slowly burn off this morning, with a quick wave of light showers moving across the region today and additional showers moving inland later tonight. The latest forecast remains on track with no updates this morning. && .SYNOPSIS...A weak frontal system will move across the area tonight into Friday, bringing the return of showers to western Washington. A stronger, wetter system will follow over the weekend, 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 persist into midweek. && .SHORT TERM /TODAY THROUGH SATURDAY/...Upper level ridging offshore will continue to flatten today, allowing for a weak frontal system to move into western Washington tonight into Friday. Expect an increase in cloud cover area-wide through the morning hours, with showers starting to push inland late this afternoon into this evening. Overall impacts with this system remain minimal, with QPF amounts expected to be rather light across western Washington. Only a few hundredths of an inch of rain are expected for most lowland locations outside of the coast, with a quarter to half an inch expected for the mountains. Increasing onshore flow in the wake of the front will help support the development of a weak convergence zone across the central Sound by Friday morning. Showers will then become more confined to the Cascades by late morning and look to taper by late afternoon. Afternoon high temperatures both days will be in the upper 50s to low 60s across the area, with overnight lows expected to be in the 40s on Friday morning. The focus then shifts to the weekend as a wetter, stronger frontal system approaches the region Saturday night into Sunday. Snow levels will rise to 7500-9500 ft in the warm sector during the day on Saturday, with some rain starting to move inland along the coast and into the North Interior throughout the day. The bulk of the precipitation will move inland Saturday night into Sunday as the front moves into the area. Southerly winds will become breezy as the front approaches, increasing to 20-30 mph across the area. .LONG TERM /SUNDAY THROUGH WEDNESDAY/...Snow levels will fall back down towards 4500 ft in the wake of the front on Sunday, bringing snow to the higher elevations of the mountains. Overall, most likely QPF amounts with this system generally range between 0.75 of an inch to 1.15 inches across the interior lowlands, 1-3 inches along the coast, and 2-4 inches across the Olympics and North and Central 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. The upper level trough trailing the frontal system will swing across the area by Sunday evening, allowing for a transient upper ridge to move into the area on Monday. While some showers will linger into Monday, expect a brief, but overall drying trend throughout the day. Confidence in the forecast details wanes heading into Tuesday and Wednesday, with ensemble clusters still showing a spread in solutions. At this time, it looks as if a few weaker systems may brush western Washington for a return to overall showery, unsettled conditions. However, will need to keep an eye on the intensity and exact placement of a ridge to the south the area as it may lessen the impacts of any subsequent systems moving towards western Washington mid to late week. 14 && .AVIATION...Mostly VFR this morning with areas of patchy fog and low stratus west of the Puget Sound generating localized IFR/LIFR conditions. This action will burn off to widespread VFR by the late morning with a wave of light VFR showers moving inland as a front works its way into the region. This will cause an increase in onshore flow with additional light showers moving inland tonight, also maintaining the threat for MVFR/IFR low stratus and patchy fog to develop tonight into early Friday morning. KSEA...VFR through the evening today with a chance for light drizzle at times at the terminal. Mid to high clouds will increase throughout the day as a series of weak fronts move inland. Conditions are favored to deteriorate early Friday morning, with a moderate chance of IFR ceilings developing (30% to 40%) below 2000 ft between 13z and 19z Fri. Winds generally out of the south to southwest between 4 to 8 kt through the period. 15 && .MARINE...Benign conditions remaining over area waters today. A weak front will arrive tonight into Friday with an increase in coastal seas (from 4 to 6 ft rising to 6 to 8 ft) but impacts are not favored. A stronger frontal system will reach the waters Saturday night into Sunday with headlines expected for most of the waters. Coastal seas will build into the double digits this weekend and could exceed 15 feet by later Sunday and remain above 10 ft into early next week. McMillian && .SEW WATCHES/WARNINGS/ADVISORIES... WA...None. PZ...None. && $$