966
FXUS66 KSEW 060257
AFDSEW

Area Forecast Discussion
National Weather Service Seattle WA
757 PM PDT Sat Jul 5 2025

.SYNOPSIS...A warming trend will begin the new week as an upper
ridge strengthens over Western Washington. The ridge will weaken
and onshore flow will increase for a brief cooling trend midweek
before warmer conditions return as an upper ridge rebuilds.

&&

.SHORT TERM /TONIGHT THROUGH TUESDAY/...The current forecast
remains on track with no planned updates. 33

Previous discussion...The warming trend begins Sunday as flow
aloft becomes more zonal. Interior temperatures will climb into
the mid to upper 70s, with some locations in the Southwest
interior and Cascade valleys reaching around 80F. By Monday, the
upper level ridge strengthens in response to strong ridging over
the Southwest US, leading to more widespread 80s across interior
areas, particularly from Seattle southward. The ECMWF and GFS
deterministic models, along with their respective ensembles, show
strong agreement on the continuation and strengthening of the
upper-level ridge through Tuesday. This will result in the warmest
temperatures of the forecast period, with low to mid-80s across
much of the Puget Sound region, and some areas pushing into the
upper 80s. Moderate HeatRisk could be a concern on Tuesday.

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...Ensemble guidance indicates
a flattening of the ridge as a trough crosses northern British
Columbia. This will promote increasing onshore flow and a
cooling trend. There`s a slight chance of a shower near the coast
or North Cascades, but the overall forecast remains dry. Upper
ridging returns late week with temperatures rising back above
normal.

&&

.AVIATION...Westerly flow aloft continues with onshore flow in the
lower levels as an upper level trough moves eastward. VFR conditions
at all of the terminals this evening with some high clouds moving
across the area. Most terminals will remain VFR for the TAF period
as the westward push is not expected to be as strong as 24 hours
ago. That said, will see MVFR conditions emerge overnight along the
coast and perhaps stretching as far east as OLM. Latest guidance
keeps both OLM and CLM VFR, further limiting inland extent.

Surface winds remaining northerly for most terminals with speeds
ranging 8-12 kts. Exceptions include HQM and CLM, being more exposed
to the direct westerly push mentioned above...although they will
retain similar speeds. Any MVFR conditions should see recovery to
VFR late Sunday morning.

KSEA...VFR conditions will continue throughout the TAF period.
Northerly winds generally 8 to 12 knots, decreasing to 5 kts or less
by 10-12Z. Wind speeds pick up again by noon Sunday, ranging 4-8
kts, with a directional shift to more westerly.

Mazurkiewicz/18

&&

.MARINE...Surface high pressure will continue to remain offshore
throughout the weekend and into early next week. Diurnal westerly
pushes down the Strait will continue over the next several
evenings, especially this evening as a Small Craft Advisory
remains in effect. A weak system may approach the area waters
during the middle of the week with an uptick in winds and seas.

Combined seas look to hover between 4 to 6 feet throughout the
weekend and into the early half of next week. Seas may become
steep at times with continuous northerly winds over the waters.

Mazurkiewicz

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...None.
PZ...Small Craft Advisory until 3 AM PDT Sunday for Central U.S.
     Waters Strait Of Juan De Fuca-East Entrance U.S. Waters
     Strait Of Juan De Fuca.

&&

$$