154
FXUS66 KSEW 221509
AFDSEW

Area Forecast Discussion
National Weather Service Seattle WA
809 AM PDT Tue Apr 22 2025

.SYNOPSIS...Dry and warming conditions are expected through Thursday
as high pressure moves into the region. Cooler conditions and
precipitation chances will return to the forecast Friday into the
weekend.

&&

.UPDATE...A few areas of patchy fog will burn off quickly this
morning. Otherwise a pleasant day is on tap across western
Washington. The current forecast is on track and no updates are
planned this morning. -Wolcott-

&&

.SHORT TERM /TODAY THROUGH THURSDAY/...Cloud cover will continue
to decrease early this morning as a dry shortwave trough digs
southward into the Pacific Northwest and high pressure builds
offshore. Clearing skies will allow temperatures to dip into the
30s for most areas this morning with patches of fog and frost
possible, especially for areas south of the Puget Sound.

A ridge of high pressure will move inland later today through
Thursday, bringing in a gradual warming trend alongside dry and
sunny conditions. Temperatures will rise to well above normal by
Thursday, with most lowland areas east and south of the Puget
Sound seeing highs in the 70s. Clouds will slowly start to move
back into the region later on Thursday as a trough slowly
approaches the coast and the upper ridge axis shifts to the east
of the Cascades.

.LONG TERM /FRIDAY THROUGH MONDAY/...A cutoff low is on track to
move inland over northern California on Friday, advecting moisture
northward towards western Washington. Precipitation will be
highly dependent on the track of the low pressure system, with
ensembles maintaining a chance of showers across the area on
Friday. Chances for light precipitation alongside cooler
temperatures continue through the weekend, with ensembles
maintaining troughing over the region through Sunday. Ridging is
favored to return by early next week, although forecast models
show differences over the timing and strength of the next incoming
system to start off next week.

15

&&

.AVIATION...Upper ridging centered offshore will continue to
build into the region today with north to northwest flow aloft.
The low level flow is northerly. Apart from patchy stratus across
north Puget Sound and outlying river valleys this morning, VFR
conditions will prevail areawide today.

KSEA...VFR. Surface winds light and variable early becoming
northerly 8 to 11 knots midday then shifting light northeasterly
tonight.   27

&&

.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.
&&

$$