995 FXUS66 KSEW 131625 AFDSEWArea Forecast Discussion National Weather Service Seattle WA 925 AM PDT Mon Oct 13 2025
.SYNOPSIS...Showers will taper across western Washington today as a weather system exits to south of the area. Weak high pressure building into the region, combined with offshore flow, and will bring cool and dry conditions to the western Washington on Tuesday and Wednesday. A weak system will bring the return of showers to the area Thursday into Friday with a stronger, wetter system expected to move into the area next weekend.
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.SHORT TERM /TODAY THROUGH WEDNESDAY/...Dry northerly flow today with gusty NE Fraser River outflow winds in the north. Winds will ease this afternoon. Precipitation has tapered off with just light showers near the south Cascades crest. Highs around 60 today. 33
Previous discussion...Radar shows showers continuing to move northwestward across the region early this morning as the upper level low that has been over the region the past several days gradually pushes to the south of the area. Expect shower activity to become more confined to the Cascades through the morning hours and to gradually taper throughout the day as the low slowly continues to exit the region. With high pressure remaining situated over British Columbia, gusty northeasterly Fraser Outflow winds have developed across portions of Whatcom County and the San Juan Islands and will continue through the morning hours. NE winds of 20 to 30 mph, with gusts to 45 mph, will remain possible through the morning, before winds start to ease this afternoon.
Cool and dry conditions are expected on Tuesday with offshore flow persisting across western Washington and weak high pressure building into the region. This drying trend, combined with decreasing cloud cover, will make for rather cool nights across the area and will bring the potential of frost to develop across portions of the interior lowlands (especially in sheltered areas away from water and areas near the Cascades) on Tuesday and Wednesday mornings. Conditions will remain cool and dry into Wednesday, though winds will transition back to onshore throughout the day. Overnight lows both days will be in the mid to upper 30s for areas across the interior and in the upper 30s to low 40s for areas near the water, with afternoon highs generally trending in the upper 50s to low 60s.
.LONG TERM /THURSDAY THROUGH SUNDAY/...Weak high pressure will remain over the area into Thursday, though guidance continues to hint at the potential for a weak front to make its way inland Thursday night into Friday for the next round of precipitation across western Washington. Afternoon highs will be in the upper 50s to low 60s and morning lows will warm some from Tuesday and Wednesday- and look to generally trend in the upper 30s and 40s. Typical fall-like weather looks return over the weekend, with a stronger, wetter system favored to arrive Saturday into Sunday. 14
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.AVIATION...An upper-low will sink southward today as light and variable flow aloft becomes more northeasterly in the afternoon and into Tuesday. Offshore flow will persist in the lower-levels throughout this time. Currently, mostly VFR cigs this morning with isolated MVFR over the South Sound. Lingering low clouds/fog this morning should burn off to VFR and mostly clear skies as drier flow aloft takes hold. Fraser river outflow winds over W Whatcom with winds gusting to 30 kt remains on tap but should peter out by the evening. Skies trending clear Monday night though with lingering surface moisture from recent showers, can`t rule out patchy fog and low clouds developing into Tuesday morning.
KSEA...VFR ceilings throughout much of the TAF period. Skies will trend clearer by Monday afternoon. Northeast wind 6 to 10 knots increasing to 10 to 15 kt today. Can`t rule out gusts near 25-30 kt in the afternoon before winds decrease in magnitude during the evening. VFR again on Tuesday.
McMillian
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.MARINE...A low pressure system will continue to move southward along the coast today, with northeasterly winds. Small Craft Advisory strength winds will continue through most of the coastal waters and Strait of Juan de Fuca before expiring in the afternoon- early evening. Fraser Outflow winds has developed bringing frequent gale gusts over the Northern Inland waters where a Gale Warning continues. As mentioned, winds will gradually decrease by the evening as the low pressure system shifts south towards California. High pressure looks to build Tuesday and into Wednesday which will bring light onshore flow through the area waters and calmer conditions. The next impactful system looks to arrive by the end of the week.
Combined seas 8 to 10 ft this morning and steep at times, decreasing to 4 to 7 ft as the day progress. Seas remain around 4 to 6 feet on Tuesday through midweek before potentially rising above 10 ft on Friday.
McMillian
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.SEW WATCHES/WARNINGS/ADVISORIES... WA...Wind Advisory until 2 PM PDT this afternoon for Lowlands of Western Whatcom County-San Juan County.
Winter Weather Advisory until 11 AM PDT this morning for Cascades of Pierce and Lewis Counties.
PZ...Small Craft Advisory until 2 PM PDT this afternoon for Central U.S. Waters Strait Of Juan De Fuca-East Entrance U.S. Waters Strait Of Juan De Fuca.
Gale Warning until 2 PM PDT this afternoon for Northern Inland Waters Including The San Juan Islands.
Small Craft Advisory until 5 PM PDT this afternoon for Coastal Waters From Cape Flattery To James Island 10 To 60 Nm- Coastal Waters From James Island To Point Grenville 10 To 60 Nm-Coastal Waters From Point Grenville To Cape Shoalwater 10 To 60 Nm.
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NWS SEW Office Area Forecast Discussion