Washington State Forecast Discussion

Western Washington


896
FXUS66 KSEW 230412
AFDSEW

Area Forecast Discussion
National Weather Service Seattle WA
912 PM PDT Tue Apr 22 2025

.SHORT TERM /TONIGHT THROUGH THURSDAY/...Current satellite imagery
shows fair weather cumulus shrinking over the Olympics and Cascades,
otherwise, clear skies over W WA this evening. A quick look at
dewpoints across the area shows the potential for another round of
overnight lows dipping into the 30s for most locations.

Inherited forecast is on track with no need for any evening updates.
For additional forecast details, please refer to the Previous
Discussion section below.

18

From Previous Discussion...Dry and mostly sunny conditions dominate
across western WA this afternoon as a ridge of high pressure noses
into the region. Another cool night is expected overnight with areas
of isolated fog and frost possible again. That said, temperatures
are expected to be slightly higher, limiting the frost extent even
more than this morning.

The ridge will shift east across the region Wednesday and Thursday
allowing for a significant warm up. By Thursday, afternoon highs
will reach into the low to mid 70s across the region.

.LONG TERM /FRIDAY THROUGH TUESDAY/...From Previous Discussion...By
Friday, a trough off the coast will elongate and cluster analysis
now slightly favors a cutoff low bringing the bulk of the energy
south of the region Friday through Sunday and leaving western WA
warmer and somewhat drier. Still there is a ~40% chance that the
trough holds together and brings more of the energy our way leading
to a wetter and cooler solution.

There remains a signal in ensemble guidance for weak and potentially
transient ridging in the Monday/Tuesday timeframe next week. All in
all, little impact is expected at this time.
-Wolcott-

&&

.AVIATION...Upper level ridge offshore moving inland Wednesday
evening. Northwesterly flow aloft with northwesterly onshore
surface gradients. Mostly clear skies. Patchy stratus Wednesday
morning will be restricted to outlying river valleys, the Chehalis
Gap, and portions of the immediate coast.

KSEA...Mostly clear skies. North wind 6 to 10 knots becoming
northeast 4 to 8 knots around 08z. Winds switching to northwest 6
to 10 knots around 18z. Felton

&&

.MARINE...A broad surface ridge centered offshore will gradually
weaken into Thursday. A weak trough moving into the Oregon offshore
waters late in the week will increase northwesterlies over the
coastal waters, but will otherwise produce little impact across area
waters. 27

&&

.HYDROLOGY...No river flooding is expected over the next 7 days.

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...None.
PZ...None.
&&