867
FXUS66 KSEW 022143
AFDSEW

Area Forecast Discussion
National Weather Service Seattle WA
243 PM PDT Wed Jul 2 2025

.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.

&&

.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 are on track to peak in the mid to upper
70s across the interior, and in the upper 50s to lower 60s along
the coast. Partly cloudy skies this afternoon will fill in later
this evening, 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.

15

&&

.AVIATION...Southwesterly flow aloft with low level onshore flow.
Pockets of MVFR stratus lingering along the coast the coast this
afternoon and 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. Have added some scattered ceilings to the TAF to reflect at
least some development late this evening with MVFR stratus near the
terminal beginning Thursday morning around 13z Southwest wind 6 to 8
knots with some gusts to 15 possible this afternoon.

&&

.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.

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...None.
PZ...Gale Warning until 3 AM PDT early this morning for Central U.S.
     Waters Strait Of Juan De Fuca-East Entrance U.S. Waters
     Strait Of Juan De Fuca.

     Small Craft Advisory from 6 PM this evening to 5 AM PDT Thursday
     for Central U.S. Waters Strait Of Juan De Fuca-East
     Entrance U.S. Waters Strait Of Juan De Fuca.

     Small Craft Advisory until 5 AM PDT early this morning for
     Admiralty Inlet.

&&

$$