


Area Forecast Discussion
Issued by NWS Seattle/Tacoma, WA
Issued by NWS Seattle/Tacoma, WA
887 FXUS66 KSEW 262230 AFDSEW Area Forecast Discussion National Weather Service Seattle WA 330 PM PDT Thu Jun 26 2025 .SYNOPSIS...A passing frontal system will bring light showers across western Washington through Friday. High pressure will build over the region this weekend into early next week, bringing a sharp rise in daytime high temperatures, peaking on Monday. This ridge will begin to weaken some going into the new week with temperatures cooling slightly and a few more clouds. && .SHORT TERM /TONIGHT THROUGH SUNDAY/...Pretty cloudy this afternoon across all of western WA (seen on satellite). The next shortwave trough is on its way inland (just offshore as of writing). It is driving a surface low pressure system that is expected to bring an occluding front through the region later today into Friday. The radar has a couple areas of showers moving through the region. A quick "waiver" pre-event round of showers is moving through the north Cascades and parts of Whatcom/Skagit Counties. A more widespread line of rain showers is approaching the coastline this afternoon. It is expected to move across all of western WA during the late afternoon and evening hours. Cloud coverage is going to remain relatively intact Friday morning as another round of showers moves through in the afternoon and evening. Most of the showers will wrap up by Saturday morning. Precipitation amounts will be relatively light across the region, with totals being several hundredths of an inch of rain (couple areas in the north Cascades may get a couple tenths of an inch). Highs today and Friday will remain cool (50s and 60s), with a few 70s by Saturday in and south of Puget Sound. The rest of the weekend will be dry as an upper level ridge builds over the Pacific Northwest (and as high pressure builds offshore). The skies will begin to clear out Saturday evening across the region, with Sunday being relatively clear. Some of the temperatures will climb into the low 80s (particularly in South Puget Sound and in some Cascade Valley areas). Remaining areas will see highs in the 60s and 70s. HeatRisk will remain minor (yellow) on Sunday. Winds will remain light through the period, but there could be some breezy north winds through Puget Sound Sunday afternoon (up to 20 mph). .LONG TERM /MONDAY THROUGH THURSDAY/...High pressure will continue into Monday, with Monday expected to be the warmest day of the week with clear skies. The warmer spots South Puget Sound and Cascade Valley areas) may see highs approach upper 80s to low 90s. This will uptick the HeatRisk into moderate (orange) in these areas. After Monday, the ridge is expected to break down and move east, giving way to a more zonal/dry flow pattern across the region. Temperatures will cool down slightly into the upper 70s/low 80s for highs through the week. There does not appear to be any chance of moisture next week (although a couple ensembles hint at a possible trough just after the 4th of July). HPR && .AVIATION...Abundant cloud cover as a weak system continues to push across Western Washington this afternoon, with rain showers pushing inland. A mix of ceilings ranging from VFR to MVFR this afternoon. Reduced visibility possible as well as the rain showers move over the terminals. Ceilings along the coast are unlikely to improve this afternoon/evening. Another weak system is expected to move over the terminals Friday morning, bringing the chance of scattered light showers after 15z. Area-wide MVFR expected to start late tonight/early Friday morning. Terminals along the coast and Strait of Juan de Fuca have the potential to see IFR ceilings, with a 30%-40% chance. Improvement into low-end VFR possible after 20z-23z for the interior terminals. KSEA...VFR ceilings this afternoon/evening with rain showers. Ceilings will decrease early Friday morning into MVFR (around 7z-8z), with the chance of another round of light scattered showers possible Friday morning. Guidance hints at some improvement as early as 20z-21z into low-end VFR. Southwesterly winds at 5-8 kt through the TAF period. 29 && .MARINE...High pressure will build over the waters late Friday and will persist into the weekend, which will lead to northwesterly flow over the coastal waters. High pressure will weaken slightly on Monday, but will be the dominant feature for next week, keeping northwesterly surface flow over the coastal waters. Marine conditions look to remain benign through next week. Westerly pushes will occur each evening across the Strait of Juan de Fuca, but at this time there is not strong signal that sustained wind speeds and gusts will meet small craft thresholds. Seas will be 3-4 ft through Friday and will increase slightly during the weekend to 4-6 ft, persisting into early next week. 29 && .SEW WATCHES/WARNINGS/ADVISORIES... WA...None. PZ...None. && $$