Area Forecast Discussion
Issued by NWS Seattle/Tacoma, WA
Issued by NWS Seattle/Tacoma, WA
521 FXUS66 KSEW 021016 AFDSEW Area Forecast Discussion National Weather Service Seattle WA 316 AM PDT Fri Oct 2 2026 .SYNOPSIS... Zonal flow aloft today with a weak system bringing precipitation chances to northern portions of Western Washington. Warm and dry conditions over the weekend as an upper level ridge builds over the Pacific Northwest. The ridge weakens on Monday and flow aloft becoming more zonal. Cooler and dry conditions next week with the return of onshore flow. && .SHORT TERM /TODAY THROUGH SUNDAY/... Latest satellite imagery shows high clouds streaming overhead, while stratus pushes inland along the coast. Zonal flow will continue over Western Washington today. A weak system moving into British Columbia will keep the chances of precipitation for northern portions of Western Washington through the afternoon. This includes the Olympic Peninsula, Whatcom and San Juan Counties. An upper level ridge will start building across the Pacific Northwest Friday afternoon through the weekend, bringing warmer and drier conditions. High temperatures along the coast will be in the low to mid 60s and along the interior in the upper 60s to low 70s. Low temperatures will be in the upper 40s to low 50s. Partly cloudy skies on today, with a few locations seeing some afternoon sun if the clouds manage to scatter out. Expect to wake up to low clouds and areas of fog across Western Washington Saturday and Sunday morning. Clouds will scatter out by the afternoon for mostly clear skies. 29 && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... There is good agreement among ensemble guidance that the upper level ridge over the Pacific Northwest will begin to flatten on Monday with a more zonal upper level pattern establishing itself over Western Washington. Onshore flow returns Monday with dry and cooler conditions favored next week. 29 && .AVIATION... A mix of VFR and MVFR cigs this morning as low stratus pushes inland along the coast. Not expecting the stratus to push east of the Kitsap Peninsula into central Puget Sound terminals. Conditions along the coast will continue to deteriorate overnight to IFR/LIFR. Southern interior terminals under clear skies and light winds may see fog development. Conditions will improve in the afternoon with widespread VFR for the interior. Along the coast, conditions will only improve to MVFR or low-end VFR. Light to calm winds early this morning will increase out of the WSW in the afternoon. Winds will become NW in the evening after 23-00Z. KSEA...VFR conditions today. Not expecting the stratus to impact the terminal this morning, as probabilities remain at 25% or less. Light WSW winds this morning will increase to 5-7 kt. Winds will shift NW around 01Z at 5-7 kt. Low cigs return Saturday morning, with current probabilities for MVFR at 40%. 29 && .MARINE... Generally high pressure over area waters through next week. A weak frontal system will move over the waters today, but no significant impacts expected with this system. A thermal trough will build along the coastline on Saturday causing surface winds over the waters to shift northerly to northeasterly through Sunday. Onshore flow returns on Monday. Models are highlighting a push of westerlies through the central portion of Strait of Juan de Fuca Sunday night into Monday morning, with the strongest winds expected to remain on the Canadian side. A stronger round of westerlies is expected Monday evening, with a 70-90% chance of winds exceeding 21 kt. Additionally, there is a 40-45% chance for gale gusts. Seas generally 3-5 ft, building up to 6 ft by Monday. 29 && .FIRE WEATHER... Fire weather concerns remain minimal through the next few days. Developing high pressure aloft this weekend with a thermal trough building up the coastline will bring warm temperatures and light offshore flow. This could result in locations in the Cascades and adjacent valleys seeing minimum RH values approach 30% on Sunday. This will be short lived, with onshore flow returning early next week to boost humidity values and bring back cooler temperatures. && .SEW WATCHES/WARNINGS/ADVISORIES... WA...None. PZ...None. && $$