


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. --568 FXUS66 KSEW 150258 AFDSEW Area Forecast Discussion National Weather Service Seattle WA 800 PM PDT Mon Jul 14 2025 .UPDATE...-- Changed Discussion --Clouds from an afternoon convergence zone over the central and south Puget Sound have since pushed southward, thinning as they go. This leaves much of the CWA under generally clear skies. Inherited forecast remains on track.-- End Changed Discussion --&& .SYNOPSIS...Dry and much warmer conditions will return Tuesday through Thursday, widespread moderate HeatRisk levels expected throughout the interior of Western Washington. In addition, elevated fire weather conditions are expected with possible critical conditions for some areas during this period. More moderate temperatures are expected late in the week and into the weekend. && .SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/...Temperatures this afternoon running 10 to 15 degrees cooler than yesterday -aided by the stronger onshore flow and mid level clouds that have settled over the interior. This will translate into near normal overnight temperatures with a few lingering clouds especially during the evening. The cooldown will be shortlived as upper level heights build quickly behind todays weak system as it moves into the Intermountain area overnight. Low level onshore flow also weakens and becomes northeasterly as a thermally induced surface trough works northward along the Oregon coast. Hires models - including the ensembles consistently show the surface trough remaining over the Oregon and SW Washington coast, if not slightly inland. This will help keep the low level more northerly than easterly for much of Western Washington. Nonetheless, highs in the interior will reach the 80s to low 90s on Tuesday, with widespread 90s on Wednesday - leading to widespread moderate HeatRisk levels over much of the interior. The immediate coast will remain in the 60s with a sharp gradient to 70s and even 80s a few miles inland. Overnight lows will also remain relatively warm especially Tuesday night into Wednesday morning, with many areas showing 50 to 70% probabilities of lows remaining in the low 60s. These odds are higher for the metro area from Tacoma to Seattle where the odds are over 90%. In addition, the N/NE winds aloft which may bring Canadian wildfire smoke into western WA Tuesday remaining generally aloft except for higher elevations in the north Cascades. The flow will turn westerly on Wednesday for less smoke intrusion over the westside. .LONG TERM /THURSDAY THROUGH MONDAY/...The pattern begins to transition Thursday with weaker low level onshore flow bringing cooler conditions to the coast Thursday- Friday. Warmer conditions will likely linger in the interior, especially the metro area where high temperatures will remain warm and in the 80s. More developed onshore flow this weekend looks to finally brings temps back to normal - but remaining dry. && .AVIATION...-- Changed Discussion --Northwest to northerly flow aloft as an upper level ridge remains offshore. Widespread VFR conditions this evening and remaining in place for most terminals for remainder of TAF period. Only exception may be HQM, as weak westerly push might be enough to bring in marine stratus for MVFR conditions overnight. Confidence is shaking in this outcome however as stratus off the coast is thinning as it retreats to the south. Majority of terminals seeing northerly winds with speeds on average 5-10 kts. These speeds expected to ease overnight, mainly in the 3-8 kts range. While some terminals remain northerly into Tuesday, other will shift more easterly, such as OLM, CLM, and PWT between 15-18Z. KSEA...VFR conditions and northerly winds for the TAF period. Wind speeds this evening still running 8-12 kts before easing to 4-8 kts by 06Z. Speeds pick back up to 8-12 kts Tuesday afternoon by 18Z. 18-- End Changed Discussion --&& .MARINE...-- Changed Discussion --High pressure remains offshore giving way to onshore flow across the area waters. A subtle shift offshore will occur on Tuesday before onshore flow returns on Wednesday with the potential for SCA winds through the strait. Have to monitor the inner coastal waters as well for small craft northerlies for both Tuesday and Wednesday. A Small Craft Advisory will continue for the outer coastal waters for elevated winds and steep seas into early Tuesday morning. Coastal seas 8 to 10 feet and will generally remain through the first half of the week, falling to 6 to 8 ft through the latter half and 4 to 6 ft by the weekend. McMillian-- End Changed Discussion --&& .FIRE WEATHER...-- Changed Discussion --As high pressure returns to the area beginning Tuesday, expect to see afternoon RH values dip down critical thresholds Tuesday afternoon with a thermal trough building north over the Cascades. While some uncertainty remains with respect to how far north and west this builds, expect to see at least some light east component to the surface winds near the Cascade gaps in zone 659 and portions of 657 and 658. As such, a Fire Weather Watch for these areas remains in effect. Confidence is lower in seeing more widespread easterly wind, but this may serve to further reduce RHs. Additionally, depending on the placement of the thermal trough, expect to see a deeper mixed layer and increased instability over the Cascades with mixing heights potentially rising into Wednesday. While confidence in the specific timing of elevated fire weather concerns is still lower, the mid week period will have the worst of the fire weather conditions for existing incidents and for the potential for any new ones were to begin. Looking ahead to the end of the week, expect conditions to moderate but remain warmer and drier than normal. However, forecast guidance continues to exhibit a large range of potential scenarios that leave confidence lower than normal. Cullen/JBB/18-- End Changed Discussion --&& .SEW WATCHES/WARNINGS/ADVISORIES... WA...Fire Weather Watch from Tuesday morning through Wednesday evening for Black Hills and Southwest Interior Lowlands- West Slopes of the Central Cascades Generally above 1500 Feet-West Slopes of the North Cascades Generally above 1500 Feet. Heat Advisory from noon Tuesday to 10 PM PDT Wednesday for City of Seattle-Downtown Everett / Marysville Area-Eastern Kitsap County-Eastside-Foothills and Valleys of Central King County-Foothills and Valleys of Pierce and Southern King Counties-Foothills and Valleys of Snohomish and Northern King Counties-Foothills and Valleys of Thurston and Lewis Counties-Foothills and Valleys of the North Cascades-Lowlands of Lewis and Southern Thurston Counties- Lowlands of Pierce and Southern King Counties-Lowlands of Western Skagit and Northwestern Snohomish Counties-Lowlands of Western Whatcom County-Middle Chehalis River Valley- Northern Hood Canal-Olympia and Southern Puget Sound- Shoreline / Lynnwood / South Everett Area-Southern Hood Canal. PZ...Small Craft Advisory until 5 AM PDT Tuesday 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. && $$