364
FXUS66 KSEW 260329
AFDSEW

Area Forecast Discussion
National Weather Service Seattle WA
829 PM PDT Fri Jul 25 2025

.UPDATE...Mostly clear conditions this evening with lingering
stratus along the coast and high clouds for northern areas.
Clouds will increase again later tonight into Saturday morning
with increasing onshore flow due to generally zonal flow aloft.
Temperatures will be a couple degrees warmer on Saturday for
highs, mainly in the mid 60s to mid 70s.

&&

.SYNOPSIS...Zonal flow will continue into Saturday, maintaining
cooler and cloudy conditions across western Washington. Southwest
flow aloft will begin to develop on Sunday, kicking off a warming
and drying trend with chances for thunderstorms towards the middle
of next week.

&&

.SHORT TERM /TONIGHT THROUGH MONDAY/...With low pressure to the
north and high pressure to the south, zonal flow aloft will
continue to bring moist onshore flow to western Washington through
Saturday. High temperatures will be limited by the cloud cover
this afternoon, reaching the upper 60s to near 70 and the upper
50s to near 60 along the coast. The weak trough over British
Columbia will shift further inland on Saturday, bringing a repeat
of cooler and cloudy conditions to western Washington. However,
slightly less cloud cover on Saturday afternoon may allow
temperatures to peak a degree or two warmer than today.

A warming trend will begin on Sunday as a high pressure ridge
begins to build over the south central US and a low pressure
system deepens over the Gulf of Alaska. While conditions will stay
dry through Monday, flow aloft will turn southwesterly and allow
temperatures to warm up several degrees. Highs will return to near
seasonal averages on Sunday and Monday with plentiful afternoon
sunshine.

&&

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...A deep upper level low
will churn offshore through the extended period, generating
southerly flow aloft over western Washington and injecting
periods of moisture northward. Ripples in the southerly flow may
generate thunderstorms throughout the week, especially over the
Cascades and Olympics, where ensembles show potential for
MUCAPE values as high as 500-1000 J/kg. While the exact details
remain highly uncertain at this time, the threat for storms
continues to be closely monitored.

15

&&

.AVIATION...The stratus has finally managed to scatter out this
evening, with the stratus staying put offshore for now. Another
marine push is expected Saturday morning, bringing area-wide MVFR
ceilings. In addition, guidance hints at a 20-40% chance of IFR
ceilings, with the highest probabilities along the Kitsap Peninsula
and coast. Some mist and drizzle is also possible. Improvements to
VFR expected after 18-21Z, although coastal terminals will may
remain MVFR due to onshore winds. A westerly push across the Strait
of Juan de Fuca will keep northwesterly winds across Puget Sound
this evening/tonight (from KSEA to KPAE), and will become more
southwesterly Saturday morning.

KSEA...VFR ceilings this evening. Another marine push is expected to
bring stratus/mist and possible drizzle in the morning (as early as
12Z), lowering conditions to MVFR. Conditions expected to improve
after 18-21Z. Guidance hints at a 20-25% chance of IFR Saturday
morning. Northwest winds this evening at 4-5 kt will become more
southwesterly Saturday morning at speeds of 4-6 kt.

29/HPR

&&

.MARINE...An upper level trough will bring increasing onshore
flow today over the region. The trough will remain in place
through Saturday before moving inland. A larger low will dip
down from Alaska offshore through next week.

For this weekend, the onshore marine pushes may bring stratus and
mist/fog over portions of the waters Saturday morning (especially
the inner coastal waters). Diurnal pushes through the Strait of Juan
de Fuca will continue through the weekend. A small craft advisory
continues for the central/east Strait of Juan de Fuca this evening,
and the push Saturday evening/Sunday may produce gusts and
potentially sustained small craft winds. Coastal seas will remain

Seas will remain 5 feet or less throughout the weekend through next
week.

HPR

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...None.
PZ...Small Craft Advisory until 2 AM PDT Saturday for Central U.S.
     Waters Strait Of Juan De Fuca-East Entrance U.S. Waters
     Strait Of Juan De Fuca.

&&

$$