Area Forecast Discussion
Issued by NWS Seattle/Tacoma, WA

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278 FXUS66 KSEW 031510 AFDSEW Area Forecast Discussion National Weather Service Seattle WA 810 AM PDT Thu Jul 3 2025 .UPDATE...
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No changes overall to the forecast this morning, updates to the aviation and marine forecasts can be found below.
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&& .SYNOPSIS...
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Seasonably warm weather with highs near normal the next couple of days are expected as a weak trough lifts through the area, bringing an increased onshore flow this weekend. A warming trend is expected by late this weekend and early next week as a ridge of high pressure aloft builds in the Western US.
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&& .AVIATION...
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Weak upper level trough remaining offshore into Friday morning. West southwesterly flow aloft becoming southerly this evening. In the lower level onshore flow continuing through Friday. Stratus deck from Skagit county to Northern Pierce county will dissipate later this morning. Ceilings mostly low end VFR in the stratus deck with pockets of MVFR. MVFR stratus deck along the coast and Puget Sound will dissipate late morning/early afternoon. Just some high clouds all areas later this afternoon into tonight. MVFR stratus deck reforming along the coast later this evening. Stratus moving inland Friday morning but staying west of Puget Sound. KSEA...Low end VFR with low level SCT clouds. Stratus expected to scatter out by 18z with just high clouds into Friday morning. Southwest wind 4 to 8 knots becoming northerly between 22z-00z this afternoon. Northerly winds continuing into Friday morning. 15
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&& .MARINE...
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High pressure will remain in place across the coastal and offshore waters this week with thermally induced low pressure east of the Cascades. A weak front will dissipate over the offshore waters Saturday. Diurnal westerly pushes through the Strait of Juan de Fuca each evening through the weekend. Friday evening looks to be the strongest push with another round of small craft advisory winds likely for the Central and Eastern Strait. Seas will remain between 4 to 7 feet through the period. 15
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&& .PREV DISCUSSION...
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/issued 318 AM PDT Thu Jul 3 2025/ SYNOPSIS...Increased onshore flow will bring seasonal conditions today. A weak trough will move inland on Friday followed by zonal flow through the weekend with mostly dry weather and average temperatures. High pressure will build into the region, promoting warmer conditions across western Washington. SHORT TERM /TODAY THROUGH SATURDAY/...An upper-low is currently traversing across BC while weak troughing resides offshore. Here locally we`re somewhere in between - in a regime of quasi-zonal flow aloft. Closer to the surface, conditions are dry but partly cloudy as weak convergence fills across the Puget Sound region and marine stratus trickles along the coast and into the SW interior. For today, pleasant weather is in store as cloud coverage gradually decrease. High temperatures will top out in the lower to mid 70s throughout interior while the coast remains cooler, generally in the 60s. Marine stratus again Thursday night, but not as expansive. Overnight lows will into the upper 40s to lower 50s. Weak troughing aloft positions overhead on Friday before exiting on Saturday. Guidance is in firm agreement with moisture remaining well east of the CWA. But, can`t rule out a slight chance (15%) of PoPs over the north Cascades on Friday evening. Zonal flow aloft will reposition on Saturday as increased onshore flow invites more cloud coverage to start the day. Seasonal temperatures are favored to continue for both Friday and Saturday with mostly dry conditions persisting as well. LONG TERM /SUNDAY THROUGH WEDNESDAY/...Zonal flow is favored to into early next week, resulting in continued seasonal temperatures and periods of morning clouds and afternoon sunshine. Then, the Four Corners High will increase in strength, leading to rising heights over the region towards midweek. Here, we could see warmer temperatures evolve into the forecast but no significant threat of HeatRisk is expected at this time. McMillian
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&& .SEW WATCHES/WARNINGS/ADVISORIES...
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WA...None. PZ...None.
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&& $$