


Area Forecast Discussion
Issued by NWS Seattle/Tacoma, WA
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Issued by NWS Seattle/Tacoma, WA
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-- Discussion containing changed information from previous version are highlighted. --158 FXUS66 KSEW 090937 AFDSEW Area Forecast Discussion National Weather Service Seattle WA 237 AM PDT Wed Jul 9 2025 .SYNOPSIS...-- Changed Discussion --A weak front will slide across western Washington today, bringing in light rain alongside cooler temperatures and locally breezy winds. High pressure will rebound by Friday, bringing a warming and drying trend through the weekend and into early next week.-- End Changed Discussion --&& .SHORT TERM /TODAY THROUGH FRIDAY/...-- Changed Discussion --An approaching weak cold front will bring a considerable cool down to western Washington today as a strong push of marine air moves into the region. A band of light rain showers and virga will continue to shift southward throughout the morning and into the early afternoon, bringing light precipitation and locally breezy winds up to 25-30 mph. The bulk of the moisture with this system will be focused over the North Cascades, where generally up to a half inch of rain is forecast, with locally higher amounts closer to an inch over the higher peaks. Elsewhere, areas along the coast and lowlands north of Everett will see up to a quarter of an inch of rain throughout the day, and rain shadowing will cause areas around the Puget Sound to see little to no rain accumulation. A convergence zone will develop later this afternoon between Seattle and Everett, with additional rainfall accumulations of a tenth of an inch over the Central Cascades and Foothills. The incoming moist marine air will cool temperatures considerably, with highs today peaking in the mid to upper 60s to low 70s for most lowland areas. Onshore flow will persist into Thursday morning, and an additional round of incoming moisture may bring a drizzle to some areas early Thursday morning while much of the region will see little more than cloudy skies lingering into the morning hours. Skies will clear by Thursday afternoon, with temperatures returning to near normal in the low to mid 70s across the lowlands. High pressure will continue to build into western Washington on Friday, allowing for a warming and drying trend. Temperatures will rebound back into the 80s for much of the interior and into the 70s along the coast. This will result in widespread Minor (yellow) HeatRisk, with pockets of Moderate (orange) HeatRisk through the Olympia and Tacoma metro areas south of the Puget Sound. .LONG TERM /SATURDAY THROUGH TUESDAY/...Ensembles continue to show good agreement over high pressure building offshore through the weekend and into early next week, allowing for warmer and dry conditions across western Washington. This will give another potential period of increased HeatRisk as well as an increase in fire weather concerns over the weekend and into early next week. However, onshore flow will keep temperatures slightly moderated through the weekend while providing decent overnight humidity recoveries. Forecast models amplify the high pressure offshore on Tuesday, allowing temperatures to climb well above normal with highs peaking in the upper 80s across the lowlands. This may bring widespread Moderate (orange) HeatRisk to the region, especially if winds shift eastward as offshore flow develops. 15-- End Changed Discussion --&& .AVIATION...-- Changed Discussion --A weak shortwave trough today will swing a weak cold front through western WA today (the flow aloft will change from southwesterly to northwesterly). VFR conditions continue as of 09Z over much of the interior terminals. Low clouds have begun to fill inland however (IFR/LIFR ceilings currently along the coast, with IFR also being reported at KSHN and KNUW - some lower visibilities also present along the coast due to mist/fog). The front has slowed a bit from the previous discussion - still expect for interior terminals to lower to MVFR between 09-12Z this morning (satellite does show increasing ceilings beginning to fill in from the southwest into Puget Sound, and to the north of KPAE). IFR/LIFR is expected to remain out of the major Puget Sound terminals (but will become widespread to the west of the sound and also over Whidbey/Strait of Juan de Fuca areas down to KPAE). Showers continue in Whatcom County this morning, with additional showers expected to develop across all remaining terminals late this morning and afternoon. Additional showers will be possible later tonight/Thursday morning, as well as a convergence zone continuing showers over Snohomish/King County through the evening. The ceilings will lift slightly through the afternoon/evening, however only isolated areas across the region will see improvement to VFR before tonight. Additionally, southwest winds will pick up 8-12 kt with gusts to 20 kt possible late this morning and afternoon - will become more westerly for most areas tonight and decrease to below 10 kt. Diffluence from a marine push through the Strait of Juan de Fuca will turn winds northerly through Puget Sound this afternoon - likely down to KBFI and KSEA after 00Z. KSEA...MVFR expected to develop (based on satellite trends/model) between 09-12Z this morning (20% chance this dips down to IFR, but looks to be lower end MVFR bases as of writing with bases). The ceilings will improve to above 2,000 feet this evening (but remain below 3,000 feet). Showers will be possible after 12Z this morning, and may remain in the vicinity of the terminal through the evening (via a convergence zone) before the next round of showers arrives later tonight. Breezy southwest winds 8-12 kt gusts to 20 kt will develop this morning, but decrease to below 10 kt as diffluence from a marine push turns the winds northeasterly after 00Z. HPR-- End Changed Discussion --&& .MARINE...-- Changed Discussion --A weak cold front and associated trough will push through the waters today. Satellite has shown some patchy fog over the coastal waters late last night into the morning. Given the patchy nature of the fog (based on satellite and observations), opted to issue a marine weather statement for the coastal waters/Grays Harbor areas through 18Z. Showers will pick up late this morning into the afternoon across the coastal waters (spreading inland across interior waters not covered from this morning`s showers in the far Northern Inland Waters). Winds will pick up out of the southwest today ahead of the front, but the only areas expected to see winds hazardous for small craft are the central/east sections of the Strait of Juan de Fuca (issued a new SCA from this afternoon through Thursday morning). A couple spots in Puget Sound may also see a couple gusts to 20 kt. Post front, heights will build offshore with high pressure remaining dominant through the weekend into next week. The flow over the coastal waters will turn northerly as a result. Some fog/low stratus will be possible again Thursday morning. Seas will increase from 2 to 4 to 6 to 8 feet this weekend, with the seas this weekend potentially becoming steep (with shorter periods). HPR-- End Changed Discussion --&& .FIRE WEATHER...-- Changed Discussion --A weak frontal system will move through the region today, with elevated onshore flow bringing in cooler and more moist conditions with some light precipitation. Wetting rains are possible across portions of the Northern Cascades and Pacific Coast. Upper ridging will then build back into Western Washington late Thursday, resulting in the return of warm, dry weather and elevated fire weather conditions on Friday. This will be the driest day of the period, with RH values dropping back into the 25% to 35% range over the mountains and across the lowlands south of the Puget Sound. Warm and dry conditions look to persist into next week but the details remain uncertain at this point to the degree of onshore flow going into next week. Conditions will warm up significantly by the middle of next week, with forecast models hinting at a shift to offshore flow and east winds through the Cascade gaps. These conditions will continue to be closely monitored. 15-- End Changed Discussion --&& .SEW WATCHES/WARNINGS/ADVISORIES...-- Changed Discussion --WA...None. PZ...Small Craft Advisory from 2 PM this afternoon to 5 AM PDT Thursday for Central U.S. Waters Strait Of Juan De Fuca- East Entrance U.S. Waters Strait Of Juan De Fuca.-- End Changed Discussion --&& $$