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FXUS66 KSEW 040323
AFDSEW

Area Forecast Discussion
National Weather Service Seattle WA
823 PM PDT Sun Aug 3 2025

.UPDATE...Mostly cloudy skies across western WA as marine stratus
has held around this evening. Thunderstorms have been observed
across the PAC NW into the evening as well, some even severe but
have stayed east of the Cascade crest. For tonight, dry conditions
are to remain but can`t rule out patchy drizzle/mist squeezing
out of stratus. Overnight lows will range between the lower to mid
50s. The previous discussion is below along with an updated
marine/aviation section:


&&


.SYNOPSIS...Cooler and dry conditions with increased cloud coverage
today through Monday as a shortwave moves across Western Washington.
Upper level troughing will continue over the region Tuesday through
Thursday, with a frontal system bringing widespread precipitation.
Conditions will dry out and become warmer into the weekend as an upper
level ridge builds over the Pacific Northwest.


&&

.SHORT TERM /TONIGHT THROUGH WEDNESDAY/...Latest satellite imagery
shows the marine stratus trying to scatter out this afternoon.
However, not expecting complete clearing as some clouds will linger
into the evening hours.

A shortwave trough will continue to bring increased cloud coverage
as it moves over Western Washington today through Monday. Conditions
are expected to remain dry with this shortwave, however onshore flow
will bring another round of marine stratus Monday morning into the
interior. The marine stratus will slowly scatter out in the
afternoon hours. Temperatures on Monday will be similar to today.
Interior high temperatures will be in the low 70s, while high
temperatures along the coast/water will be in the low to mid 60s.
The shortwave feature will exit the region Monday evening. An upper
level trough right behind the shortwave will move into the region
and remain the dominant upper level feature for the next few days as
it slowly moves across. Compared to the last trough, this trough
will bring more moisture into Western Washington, bringing  back
precipitation chances to Western Washington. As for Tuesday,
precipitation is expected to stay mostly west of Puget Sound. QPF
values will be on the light side for most locations Tuesday (<0.10
inches), while locations along the north coast will see the highest
QPF values. On Wednesday, precipitation will be more widespread as a
frontal system moves through the region. Guidance shows that the
highest QPF values will be centered along the coast, Olympics, and
northern Cascades.

.LONG TERM /THURSDAY THROUGH SUNDAY/...Upper level troughing will
continue into Thursday, with post-frontal showers. Shower activity
will gradually taper off throughout the day on Thursday. Long-term
models favor an upper level ridge developing over Pacific Northwest
Friday into the weekend. This ridge will bring drier and warmer
conditions to the region. High temperatures will gradually increase
each day into the weekend. High temperatures on Friday will rebound
into the mid to upper 70s along the interior, and along the coast
temperatures will be in the mid to upper 60s. By Sunday high
temperatures along the interior will be in the mid to high 80s,
while along the coast/water high temperatures will be in the low
70s.

29

&&

.AVIATION...Weak upper level trough offshore moving inland
overnight will be east of the area by Monday afternoon.
Southwesterly flow aloft becoming light with the trough overhead
then westerly behind the trough.

Low level onshore flow continuing through Monday. Mostly VFR ceilings
this evening with localized MVFR ceilings near KPAE until 03z.
Ceilings lowering back down to MVFR 07z-10z with MVFR ceilings
through most of the morning Monday.

KSEA...VFR ceilings near 4000 feet. Clouds could scatter out for a
few hours this evening before MVFR ceilings redevelop after
midnight. MVFR ceilings continuing through most of Monday morning.
Southwest wind 4 to 8 knots.

&&

.MARINE...Surface high pressure will remain over the waters through
Monday with lower pressure over Eastern Washington. A frontal
system will move through the waters later Tuesday into Wednesday,
High pressure will rebuild over the waters Thursday and Friday.

Small craft advisory westerly winds in the Central and Eastern
Strait of Juan de Fuca tonight and again Monday night.


&&


.SEW WATCHES/WARNINGS/ADVISORIES...
WA...None.
PZ...Small Craft Advisory until 5 AM PDT Monday for Central U.S.
     Waters Strait Of Juan De Fuca-East Entrance U.S. Waters
     Strait Of Juan De Fuca.

     Small Craft Advisory from 5 PM Monday to 5 AM PDT Tuesday for
     Central U.S. Waters Strait Of Juan De Fuca-East Entrance
     U.S. Waters Strait Of Juan De Fuca.

&&

$$