799
FXUS66 KSEW 161627
AFDSEW

Area Forecast Discussion
National Weather Service Seattle WA
927 AM PDT Wed Apr 16 2025

.SYNOPSIS...A dry, warmer pattern will continue through Friday
across Western Washington with upper ridging. A weak frontal
system will move through on Saturday with cooler temperatures and
increasing shower potential. Additional shower chances and cooler
temperatures Sunday into Monday with troughing over the Pacific
Northwest.

&&

.SHORT TERM /TODAY THROUGH FRIDAY/...Satellite imagery shows
consolidated stratus deck over Lower Chehalis Valley and along the
Central Coast dissipating at 9 am/16z. Just some patchy low
clouds over the remainder of the area. Temperatures were in the
mid 40s to lower 50s.

Forecast on track this morning. Upper level trough moving by to
the east later today will enhance the northwesterly surface
gradients. This in turn will keep high temperatures in the upper
50s to mid 60s even with a sunny afternoon. Upper level ridge
building into the British Columbia coast Thursday with the ridge
axis moving over Western Washington Friday. Slow warming trend
peaking on Friday with lower 70s likely in the interior from
about Seattle south. Current forecast on track. No update this
morning. Previous long term discussion follows with updated
aviation and marine sections. Felton

.LONG TERM /SATURDAY THROUGH TUESDAY/...The upper ridge will
flatten over the Pacific Northwest Friday night into Saturday as a
weak frontal system moves across Western Washington. An uptick in
precipitation potential is expected during this period, although
QPF amounts are generally light (under 0.10" for the lowlands),
and favored in the Cascades as well as in any convergence areas.
Ensembles are in good agreement that troughing remains in place over
the Pacific Northwest Sunday into Monday for continued cooler
temperatures. Weak ridging may again build into the region Tuesday.
Temperatures are expected to range near to slightly below normal
over the weekend and into early week. JD

&&

.AVIATION...Northwesterly flow aloft this morning will turn more
northerly this afternoon as an upper level trough dives southward
into eastern Washington throughout the day. Surface winds turning
northerly by late morning with speeds increasing to 10-15 kts
especially for the eastern half of the CWA.

Widespread VFR conditions over W WA this morning with most terminals
reporting clear skies or only high clouds. The exception being a
patch of clouds present over the southwest interior and coast. VFR
conditions are expected to remain in place for all terminals for the
entire TAF period.

KSEA...VFR conditions in place and expected to remain that way for
the TAF period. Northerly winds 5-10 kts this morning before an
increase in speed to 10-15 kts around 20Z with possible gusts
impacts the terminal this afternoon. These speeds will gradually
ease by 12Z Thursday.

18/McMillian

&&

.MARINE...High pressure over the northeastern Pacific
extending over the waters will continue into Friday. A pair of
weak systems will move through the area over the weekend.

Combined seas over the coastal waters in the 10 to 12 foot range
through Wednesday. Seas for the outermost coastal waters could reach
14 feet throughout the day today. Winds as high as 30 knots in the
outer coastal waters still possible early this morning before
gradually easing. Inherited SCA for the coast looks good and remains
in effect until 6 PM this early evening. While current forecast
suggests speeds should remain just under criteria, isolated
northerly winds in Puget Sound might encroach on SCA criteria. This
will need to be monitored. A Small Craft Advisory for rough bar
conditions at the Grays Harbor Bar also looks valid and will
therefore go untouched. Seas subside tonight back into the 4 to 6
foot range later Thursday and Thursday night.

18

&&

.HYDROLOGY...No river flooding the next 7 days.

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...None.
PZ...Small Craft Advisory until 6 PM PDT this evening for Coastal
     Waters From Cape Flattery To James Island 10 To 60 Nm-
     Coastal Waters From Cape Flattery To James Island Out 10 Nm-
     Coastal Waters From James Island To Point Grenville 10 To
     60 Nm-Coastal Waters From James Island To Point Grenville
     Out 10 Nm-Coastal Waters From Point Grenville To Cape
     Shoalwater 10 To 60 Nm-Coastal Waters From Point Grenville
     To Cape Shoalwater Out 10 Nm-Grays Harbor Bar.

&&

$$