167
FXUS66 KSEW 222257
AFDSEW

Area Forecast Discussion
National Weather Service Seattle WA
257 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 afternoon, with rain
through this evening focused along the Olympic Peninsula, and
north of Snohomish County (mainly in the Cascades). A cold front
will the slide southeast across Western Washington tonight into
Sunday bringing steadier rainfall to the lowlands. Southerly
winds will also increase tonight, with gusts ranging 20 to 35
MPH for most areas, strongest near Whidbey Island and near
Bellingham. 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...MVFR ceilings are favored for the majority of TAF
period. Some guidance indicates that there could be some
improvement this afternoon/evening. However, confidence is low
at this time. It`s possible to see ceilings bouncing around
between high-end MVFR and low-end VFR. MVFR ceilings expected
overnight and will persist throughout the day on Sunday.
Localized IFR is also possible between 10Z-20Z Sunday; currently
the highest chances are for PWT and OLM, with a 35-40% chance.
Other terminals have a 10-25% chance of IFR. A frontal system
will bring rain to area terminals. Rain showers will continue at
the coast this afternoon, and the main band of rain will push
inland late tonight reaching interior terminals by 07Z-08Z.

Breezy winds this afternoon will continue into Sunday morning, with
sustained speeds of 8-12 kt and gusts 20-25 kt. Winds will gradually
subside after 18Z Sunday. Latest guidance suggests a convergence
zone may form behind the front likely as early as 19Z around PAE and
make it as far south to BFI and SEA by 21Z.

KSEA...MVFR at the terminal this afternoon. May see some improvement
to high-end MVFR/low-end VFR at the terminal between 00Z-06Z, but
confidence is low and rather expect ceilings to bounce back and
forth between VFR and MVFR at times. MVFR ceilings will continue
into Sunday as a frontal system pushes through the terminal. There
is a small chance (20-25%) of IFR between 12Z-21Z as the main band
of rain pushes through. Breezy southwesterly winds this afternoon
through Sunday morning, with gusts up to 20 kt. Guidance suggests a
convergence zone may form after 19Z Sunday around PAE and shift
southward into SEA, with N/NE winds impacting the terminal between
23Z-06Z.

29

&&

.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 from 7 PM this evening to 7 AM PST Monday
     for East Entrance U.S. Waters Strait Of Juan De Fuca.

     Small Craft Advisory from 7 PM this evening to 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.

&&

$$