FXUS66 KSEW 030324

AFDSEW



Area Forecast Discussion

National Weather Service Seattle WA

824 PM PDT Wed Jul 2 2025



.UPDATE...No significant changes to the forecast this evening.

Please refer to an updated aviation section below.



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.SYNOPSIS...Onshore flow will maintain a cooling trend for 

western Washington through Thursday, with continued morning 

stratus and afternoon sunshine. A weak trough will move inland on

Friday, increasing zonal flow through the holiday weekend with

mostly dry and mild conditions. High pressure will build over the

southwestern US by the middle of next week, promoting warmer 

conditions across western Washington.



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.SHORT TERM /TONIGHT THROUGH SATURDAY/...A longwave trough slowly

passing over British Columbia is generating onshore flow across

western Washington, with temperatures cooling several degrees from

yesterday. Highs today peaked in the mid to upper 70s across the 

interior, and in the upper 50s to lower 60s along the coast. 

Partly cloudy skies this evening will fill in tonight, with 

another round of morning stratus expanding eastward from the 

Pacific Coast across the Chehalis Basin and over the Puget Sound 

early Thursday morning. Some areas may see a drizzle below the 

stratus in the morning, but conditions will clear up by the 

afternoon and give way to another partly cloudy afternoon with 

plenty of sun breaks. Temperatures Thursday will be a few degrees 

cooler than today, with highs in the low to mid 70s across the 

interior and closer to 60 degrees for areas by the water.



A weak trough will lift across the Pacific Northwest on

Independence Day, resulting in little more than partly cloudy

skies and near-normal temperatures across western Washington for

the holiday. Forecast models are in good agreement that the bulk 

of the moisture associated with this system will stay to the east 

of the Cascade crest, but there is potential for isolated light 

shower activity over the Cascades Friday evening. Zonal flow will

develop on Saturday as the trough moves inland, with continued

mild conditions and morning cloud cover. Highs Friday and Saturday

will stay fairly steady, reaching the mid to upper 70s across the

interior and the low to mid 60s along the coast.



.LONG TERM /SUNDAY THROUGH WEDNESDAY/...Zonal flow is favored to

continue into early next week, resulting in continued mild

conditions with periods of morning clouds and afternoon sunshine.

A ridge of high pressure will build over the southwestern US 

towards the middle of next week, signaling a return of warmer

temperatures across western Washington, but the degree of warming

remains uncertain at this time.



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.AVIATION...Southwesterly flow aloft with low level onshore flow. 

Pockets of MVFR stratus lingering along the coast the coast this 

evening will fill tonight 03z-06z then move inland overnight. HREF 

ensembles showing a 30-40% chance of MVFR ceilings developing from 

KSEA to KPAE as early as 05/06Z and 60-80% chance by 12/14Z. Expect 

more widespread stratus development to linger a bit longer into 

Thursday morning before lifting and mixing out 17/18Z. 



KSEA...VFR conditions with some high clouds will linger through the 

evening. As noted above, high-res ensembles showing a 30-40% chance 

of ceilings below 3kt ft as early as 05/06z and higher odds by 

13/14z. Winds are bouncing between southwest and occasional 

northwesterlies but are seeming to settle into a more southwesterly 

pattern. KBFI was NW but seems to be settling into southwesterly as 

well. High OVC to BKN layers at both terminals. 



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.MARINE...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. 



A typical diurnal pattern with westerly pushes through the Strait of 

Juan de Fuca each evening through the weekend. The small craft 

advisory remains in effect for tonight for the Central and Eastern 

Strait with gusts to 30 knots possible. Thursdays push looks to be a 

bit weaker, with the push Friday looking more likely to result in 

another round of small craft advisory conditions for the Central and 

Eastern Strait.



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.SEW WATCHES/WARNINGS/ADVISORIES...

WA...None.

PZ...Small Craft Advisory until 5 AM PDT Thursday for Central U.S. 

     Waters Strait Of Juan De Fuca-East Entrance U.S. Waters 

     Strait Of Juan De Fuca.



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