115
FXUS66 KSEW 230342
AFDSEW

Area Forecast Discussion
National Weather Service Seattle WA
742 PM PST Sat Nov 22 2025

.SYNOPSIS...A frontal system will move southwards across Western
Washington into Sunday for increasing precipitation. An upper
trough will move inland on Monday for additional light showers.
A wetter system will move through Wednesday and Thursday for
heavier precipitation, mountain snowfall, and locally breezy
winds. Cooler temperatures likely by late week.

&&

.SHORT TERM /TODAY THROUGH MONDAY NIGHT/...A frontal system
remains stalled over British Columbia this evening, with latest
radar showing the main band of precipitation mainly focused
along the northern tier of Olympic Peninsula and Whatcom County
(mainly the Cascades) tonight. A cold front will the slide
southeast across Western Washington late tonight into Sunday
bringing steadier rainfall to the lowlands. Southerly winds have
started to increase tonight. Gusts are expected to primarily
range between 20 to 35 MPH for most areas and be the strongest
near Whidbey Island and near Bellingham. Overall, the forecast
largely remains on track this evening, with no significant
updates needed. The remainder of the previous discussion follows
below, with updates made to the aviation section. 14

Precipitation will be mainly confined to the Cascades Sunday
afternoon in a post- frontal airmass. In addition, a convergence
zone will develop around midday Sunday over King and Snohomish
Counties, resulting in continued showers at times, especially
from Everett to SeaTac. Snow levels will also lower near 2000 to
3000 feet by Sunday evening, resulting in accumulating snow for
the Cascade Passes at times through Monday. Snowfall
accumulations Sunday into Monday are expected to range between 3
to 6 inches for Stevens and Snoqualmie Pass, with locally
higher amounts in the convergence zone. If you`re traveling over
the Passes late Sunday through Monday, monitor the weather
conditions and pass information.

Another round of light precipitation is expected elsewhere on
Monday as the upper trough moves inland. However, amounts are
expected to remain light. Temperatures will cool on Monday with
highs in the mid to upper 40s.

&&

.LONG TERM /TUESDAY THROUGH FRIDAY/...A brief break in the
precipitation on Tuesday morning as ridging begins to build
across the Western US. However, a warm front will approach
Western Washington late Tuesday, resulting in increasing
precipitation. This will begin a period of wetter weather that
will continue through Thursday as the next weather system taps
into subtropical moisture. Periods of lowland rain are expected
Wednesday through Thursday with the frontal system.

In addition, snow levels will remain lower at the onset of the
precipitation, likely ranging between 2000 to 3000 feet,
resulting in snow over the Cascade Passes Tuesday night into
Wednesday morning. Snow levels will then rise to near 4500 to
5500 feet by late Wednesday. However, east flow at the surface
may result in a brief period of wintry mix or freezing rain for
the Cascade Passes on Wednesday. There remains uncertainty in
the orientation of the warm front midweek and how quickly
temperatures warm over the Cascades. Either way, snow at the
onset (and potentially brief freezing rain) may result in
difficult pass conditions midweek. If you are traveling over the
Passes beginning late Tuesday for the holiday, continue to
monitor the weather forecast.

Uncertainty in ensembles begins to increase Friday, however, a
signal for continued troughing will allow for unsettled weather
late week, and have kept NBM POPs at this time. Otherwise,
temperatures will warm a few degrees above normal Wednesday and
Thursday with highs in the low to mid 50s. JD

&&

.AVIATION...Terminals across the area are primarily VFR to MVFR
tonight. Expect more widespread MVFR conditions to develop
overnight and to persist through the day on Sunday as a frontal
system sags southward and brings the next round of more widespread
rain to the area terminals. Localized IFR conditions will be
possible at times, primarily between 10Z-20Z Sunday as the rain
moves through. At this time, PWT and OLM still have the highest
chances of seeing conditions lower to IFR, with guidance indicating
roughly a 35-40% chance of occurrence. The remainder of the
terminals have roughly a 10-25% chance of IFR conditions
developing on Sunday. Light showers will continue to move into
the area ahead of the front tonight, but expect the main band
of rain to gradually sink southeastward across the area late
tonight into early Sunday. More widespread rain will likely
reaching the interior Puget Sound terminals between 10Z-14Z.

Southerly winds have increased this evening and will remain
breezy into Sunday morning, with sustained speeds generally
between 8-14 kt and gusts to 20-25 kt. Winds will ease again
after 18Z Sunday. A convergence zone may develop behind the
front, likely between 18-20Z around PAE, and sink southward to
BFI and SEA around 21Z.

KSEA...MVFR conditions persist at the terminal tonight and are
expected to continue into Sunday as a frontal system sags
southeastward through the terminal. There is a small chance
(20-25%) of IFR conditions developing at the terminal between
12Z-21Z as the main band of rain pushes through. Southerly winds
have increased to 8-12 kt this evening and may be breezy with
gusts to 20 kt at times through 18Z Sunday. A convergence zone
may shift southward into SEA, likely between 21-23Z and may
briefly bring a period of N/NE winds and lower cigs/vis to the
terminal.

29/14

&&

.MARINE...A weather system will move across the waters through
Sunday, bringing increasing winds. Small Craft Advisories are in
effect for all waters into Sunday due to the increased winds.
Gusts are expected to range between 20 to 30 kts for most waters
into Sunday morning, with brief gusts near 35 kts possible for
Admiralty Inlet and Bellingham Bay. Winds will then transition
more westerly on Sunday, with SCA west winds through the central
and eastern portions of the Strait of Juan de Fuca. There may
also be brief gale force wind gusts in the eastern Strait of
Juan de Fuca Sunday afternoon, however, winds are expected to
predominantly remain below 35 kts. Winds will then slowly
subside Sunday night into Monday. South winds will increase
again on Tuesday as another frontal system moves into the
waters. Winds will likely remain elevated through at least
Thursday as the system stalls over the area. Additional
headlines are expected late Tuesday through Thursday.

Seas of 10 to 13 feet will continue through Sunday before
subsiding below 10 feet Monday into Tuesday. Seas are expected
to build above 10 feet, especially for the outer Coastal Waters,
midweek with the next weather system. JD

&&

.HYDROLOGY...A weather system will move across western
Washington tonight into Monday for lowland rain and mountain
snowfall. No river flooding is expected during this period, but
rivers will rise. Heavier precipitation is likely beginning late
Tuesday through Thursday next week. Snow levels will also rise
to 5000 to 6000 feet by Thursday, resulting in additional rises
on rivers. At this time, the Skokomish River in Mason County is
forecast to approach flood stage midweek. Although no
additional river flooding is forecast at this time, rivers will
continue to be monitored. JD

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...None.
PZ...Small Craft Advisory until 4 PM PST Sunday for Grays Harbor
     Bar.

     Small Craft Advisory until 10 PM PST Sunday for West Entrance
     U.S. Waters Strait Of Juan De Fuca.

     Small Craft Advisory from 7 AM Sunday to 7 AM PST Monday for
     Central U.S. Waters Strait Of Juan De Fuca.

     Small Craft Advisory until 7 AM PST Monday for East Entrance
     U.S. Waters Strait Of Juan De Fuca.

     Small Craft Advisory until 7 AM PST Sunday for Admiralty Inlet-
     Northern Inland Waters Including The San Juan Islands-
     Puget Sound and Hood Canal.

     Small Craft Advisory until 10 AM PST Monday 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.

&&

$$