872
FXUS66 KSEW 212316
AFDSEW

Area Forecast Discussion
National Weather Service Seattle WA
316 PM PST Fri Nov 21 2025

.SYNOPSIS...
Drier conditions will linger tonight into Saturday for much of
the region. Widespread precipitation - lowland rain, mountain
snow - with breezy winds will move into the area from the North
Saturday night into Sunday. Cooler and unsettled weather will
continue into Monday, with an increased potential for an
organized system mid week into the Thanksgiving Holiday.

&&

.SHORT TERM /TONIGHT THROUGH SUNDAY NIGHT/...
A frontal system over British Columbia will kick off the
weekend, resulting in increased clouds over western Washington
and some rain at times across the northern Olympic Peninsula
and northern interior. Onshore flow will increase Saturday
afternoon with breezy winds along the northern coast and
Whidbey Island northward. This will also preclude the relatively
slow shift of the system over British Columbia southward into
western Washington Saturday night into early Sunday morning.
This will bring widespread precipitation and breezy winds
through Sunday. Snow levels Sunday morning will start around
5500-6000 ft gradually lowering to near 2000-2500 ft late Sunday
night. This will set the stage for expected accumulations
across all the mountain passes with a 60-70% chance of 1-2
inches by 10PM Sunday night.

&&

.LONG TERM /MONDAY THROUGH FRIDAY/...
 Precipitation - especially over the higher terrain is expected
to linger into Monday - aided by the potential for a post
frontal convergence zone as well as a weak upper level shortwave
expected to clip the region. Snow levels will remain in 1500 to
2000 feet Monday, with storm total accumulations at the passes
in the 4 to 6 in range from Sunday through Monday.
Precipitation will taper off Monday evening with weak ridging
is favored to briefly dry out conditions on Tuesday, with
Tuesday morning looking to be the coldest of the week - some
lowland locations especially away from the water will dip to
near freezing.

Ensembles continue to show the potential for a second Pacific
storm system to move into the region mid-week into the
Thanksgiving holiday - bringing another round of widespread
precipitation and breezy/gusty conditions. Snow levels at or
near pass levels on Wednesday would leave the door open for
potential snow accumulations and/or a wintery mix of
precipitation, including a small chance of freezing rain. This
has the potential to cause travel impacts especially for those
traveling across the Cascades ahead of the holiday. Beyond this
ensembles continue to highlight active and potentially
impactful weather through the weekend, especially through the
higher terrain.


&&

.AVIATION...The Pac NW is under westerly flow tonight a system
stalls over southern British Columbia. Scattered showers will
mostly affect the coast, strait and north interior. The low
level air mass remains moist with FEW-SCT layer around 1500-3000
ft, with BKC-OVC mid and high clouds aloft. Expect MVFR
conditions early Saturday morning that may persist through much
of the day. Rain increases in coverage Saturday night as this
system over B.C. shifts south into western WA. 33

KSEA...VFR tonight with S winds to 10 kt. Lowering clouds and
MVFR cigs by 12-15z which will persist through much of Saturday.
33

&&

.MARINE...Seas remain elevated, 10-13 ft, and a Small Craft
Advisory remains in effect for the Coastal Waters and West
Entrance through Saturday (and possibly into Sunday too). Winds
through Saturday will generally range in 10-15 kt with a few
gusts to 20 kt in the Northern Inland Waters. Winds will flip to
W-SW on Sunday as a front tracks through. Expect strong winds
through the Strait of Juan de Fuca with gales possible. Onshore
flow prevails early next week with high pressure offshore. Winds
will turn offshore again by Tuesday as the next systems
approaches from the west. 33

&&

.HYDROLOGY...
A weather system will move across western Washington late
Saturday into Monday for lowland rain and mountain snowfall. No
river flooding is expected during this period, but rivers will
rise. The potential exists for additional, heavier precipitation
during the middle of next week. However, uncertainty exists in
both the location and duration of precipitation. River levels
will continue to be monitored during this mid to late week
period.

JD

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...None.
PZ...Small Craft Advisory until 4 PM PST Saturday 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-
     West Entrance U.S. Waters Strait Of Juan De Fuca.

&&

$$