619 FXUS66 KSEW 191001 AFDSEWArea Forecast Discussion National Weather Service Seattle WA 301 AM PDT Fri Sep 19 2025
.SYNOPSIS...Dry and mild conditions will continue today ahead of widespread rain, breezy winds, and cooler temperatures over the weekend. Conditions will dry out early next week as high pressure builds into the region, with chances for more precipitation mid week.
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.SHORT TERM /TODAY THROUGH SUNDAY/...High pressure will build inland today as a weak trough shifts east of the Cascades. Temperatures will warm up a few degrees with highs in the 70s across the lowlands and in the 60s along the water. Skies will remain clear through the afternoon, with marine stratus creeping inland along the coast by the evening as onshore flow increases. However, smoke from area wildfires will continue to cause hazy conditions across western Washington.
The next weather system will enter the region later on Saturday, swinging a cold front inland. Rain will fill in along the coast by the afternoon and cross the region in the evening into Sunday morning. Most areas will dry out by Sunday afternoon, with forecast models suggesting the formation of post-frontal convergence zone showers over the central Puget Sound. Rainfall totals over the weekend are on track to range from 0.25 to 0.50 inches over the lowlands, and generally 0.50 to 1.50 inches over the mountains. Alongside rain, the incoming cold front will bring locally breezy winds around 20 to 30 mph, as well as cooler temperatures on Sunday that will peak in the 60s for most areas.
.LONG TERM /MONDAY THROUGH THURSDAY/...High pressure will build inland in the beginning of next week, bringing warmer and drier conditions to the region. Chances for rain increase towards the middle of next week, with potential for cooler conditions and more widespread precipitation.
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.AVIATION...West to northwest flow aloft as we return to a more zonal pattern. Clear skies this morning over western Washington. Most terminals are VFR. Isolated areas of fog are developing, however, at BLI and near HQM. Given the current trends this morning, thinking that marine stratus will be very isolated if it able to develop, rather, localized areas of fog will be what develop this morning, spreading to other terminals such as OLM and perhaps PWT. Fog will be shallow, and therefore burn off fairly quickly (from 15- 17Z). Clear skies will prevail through the day today. Models are more confident on marine stratus forming along the coast Saturday morning. Winds are mostly calm this morning, during the day winds will remain northerly 5-10 kt.
KSEA...VFR conditions with clear skies through the TAF period. Winds NNE 5 kt or less this morning becoming NW 8 to 12 kt during the day.
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.MARINE...High pressure will remain over the coastal waters today. It will begin to weaken tonight as a frontal system moves through the waters Saturday night into Sunday. Southwesterly winds will increase ahead of the front on Saturday, with the strongest winds associated with the frontal passage Saturday night into Sunday morning. The areas with the best chance of seeing Small Craft Advisory winds will be through the central Strait of Juan de Fuca, though winds my briefly reach criteria throughout the interior waters as the front moves through. A push of westerly winds will follow behind the front for Sunday, with more SCA winds through the central Strait of Juan de Fuca. High pressure rebuilds on Monday before another weakening front approaches the coastal waters on Tuesday.
Seas around 4 to 6 ft today will increase back to 7 to 9 ft through the weekend. Seas will hover around 6 to 8 ft through early next week.
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.SEW WATCHES/WARNINGS/ADVISORIES... WA...None. PZ...None. &&
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NWS SEW Office Area Forecast Discussion