565
FXUS66 KSEW 021032
AFDSEW

Area Forecast Discussion
National Weather Service Seattle WA
232 AM PST Tue Dec 2 2025

.SYNOPSIS...
Upper level ridge offshore through Thursday. Weak system moving
south out of the area later this morning into the afternoon.
Weak warm front will brush the northwest corner Wednesday.
Another system moving over the top of the ridge moving through
Thursday. Ridge offshore weakening Thursday night into Friday. A
series of stronger and wetter systems will take aim at Western
Washington beginning Friday and continuing through the middle of
next week.

&&

.SHORT TERM /TODAY THROUGH THURSDAY/...
Satellite imagery shows cloudy skies over Western Washington.
Upper level trough axis moving into the northern portion of the
area early this morning. Doppler radar has an area of rain
over Snohomish and King county extending back to the northwest
over Whidbey Island and eastern Clallam and Jefferson county.
Temperatures at 2 am/10z were in the upper 30s to mid 40s.

Weak system moving south through Western Washington this
morning with rain chances coming to an end from north to south
this afternoon. Even with the system out of the area light flow
in the lower levels combined with plenty of low level moisture
will keep skies cloudy over most of the area. Some clearing
possible along the North Coast. Little in the way of daytime
"heating" with the cloud cover as well. Highs in the mid 40s to
lower 50s.

Western Washington in-between systems tonight. Like the
afternoon hours, light flow in the lower levels with low level
moisture will keep skies at least mostly cloudy. Could see some
fog form overnight especially in the fog prone locations like
the Southwest Interior. Lows mid 30s to lower 40s.

Weak warm front moving over the top of the offshore ridge
brushing the northwest portions Wednesday for a chance of rain.
For the remainder of the area, even if the lower cloud deck
breaks up a little the middle level clouds associated with the
warm front will keep skies mostly cloudy. Highs in the mid to
upper 40s.

Yet another system riding over the upper level ridge offshore
reaching Western Washington Thursday. Leading edge of the rain
could reach the northern half of the area after midnight early
Thursday morning. Rain spreading over the entire area Thursday
morning with rain continuing into the afternoon hours. Highs in
the mid 40s to lower 50s. Felton

&&

.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
Extended models continue to show good agreement with the
offshore ridge weakening Thursday night into Friday. Another
system moving over the top of the flatting ridge reaching
Western Washington Friday. This system has a weak sub tropical
moisture tap associated with it but the system is also
progressive. Friday night the system will move southeast of the
area. Another weak impulse embedded in the now westerly flow
aloft arriving Saturday keeping rain in the forecast. Elongated
system stretching along the British Columbia coast down into
Western Washington Sunday for more rain. Windy conditions along
the coast and over the Northwest Interior possible with this
feature. There could be a short break Sunday night or Monday as
an upper level ridge tries to build over the area. Ensembles
solutions indicating the ridge being strong enough to push yet
another system to the north running around a third of the
solutions. This next system is the juiciest one of the series
with a consolidated tap into subtropical moisture. Right now
even if the ridge builds enough to deflect the system north it
will only be a one day reprieve with the ridge weakening Tuesday
and numerous ensemble solutions indicating significant
precipitation.

In addition to the rain, high tide cycle combined with these
systems will bring up the possibility of coastal flooding due
to tidal overflow along the coast, Strait of Juan de Fuca and
over the Northern Inland Waters beginning with the high tides
Friday and continuing into the early part of next week. Felton

&&

.AVIATION...
A cold front will continue to progress through western
WA this morning as a shallow trough digs southward. The ridge
following behind along the Pacific Coast will increase northerly
flow aloft today. Showers this morning are primarily concentrated
along and east of I-5. The activity will consolidate down to a
convergence zone between Snohomish/King Counties through late
morning. Ceilings are decreasing as the front moves through, and
will likely range from 500 ft up to 1,500 ft (IFR-MVFR) with pockets
of LIFR. Some mist may accompany the low ceilings at times. Due to
the abundant low level moisture/light flow, most terminals will only
improve to MVFR (only the coast will have the best chance of
ceilings above 2,000 ft this evening) before ceilings lower again to
IFR-MVFR (pockets of LIFR). South winds 4-8 kt will switch to the
north behind the front 3-6 kt through the morning (5-10 kt along the
coast). The speeds will decrease tonight to less than 5 kt and
switch to the south.

KSEA...Rain showers from a nearby convergence zone will continue in
and near the terminal through late Tuesday morning. Ceilings will
continue to lower this morning - confidence remains high in IFR cigs
from 12Z through 20Z due to the surface moisture (lower chance that
it dips down to LIFR criteria). MVFR improvement up to 2,000 ft is
expected late this afternoon and evening with another elevated
chance of IFR ceilings Wednesday morning. South winds 4-8 kt will
switch to the north around 15-18Z but are expected to decrease to 3-
6 kt through the day, then become calm or very light southeast wind
after 09Z.

HPR

&&

.MARINE...
A cold front has pushed through the coastal waters this
morning and will continue to track through the interior waters.
Gusty winds up to 25 kt remain likely in the outer coastal waters
through Tuesday afternoon, as will seas of 9-12 ft through late
tonight. The small craft advisory was extended to 06Z Wednesday for
the slower drop in seas. Benign conditions are expected with light
winds, and seas returning to 4-6 ft Wednesday through Friday. A
stronger system will approach the waters Friday through the weekend
into next week with gusty winds at times for most of the waters. The
best chance of gale force winds will be in the Strait of Juan de
Fuca Monday night into Tuesday. Seas increase back to 9-12 ft
Saturday, and potentially increase to 10-14 ft early next week.

HPR

&&

.HYDROLOGY...
The series of weather systems forecast to reach the area will
eventually increase the threat of river flooding in the coming
days. West northwesterly flow aloft with the system Friday puts
the area of greatest precipitation in the North Central
Washington Cascades. Snow levels rising over 6000 feet. Current
forecast 18 hour precipitation amounts between 06z Friday and
00z Saturday have an area of 2 inch bullseyes between Snoqualmie
Pass and Glacier Peak. This will put pressure on the rivers
flowing out of this area including but not limited to the
Snoqualmie, Skykomish, Snohomish and Tolt rivers.

As the flow aloft becomes more west southwesterly the flood
threat will shift to the flood prone Skokomish River later in
the weekend.

Plenty of uncertainty on how the pattern will set up early next
week but there is a chance for a widespread river flooding
event.

The landslide threat is minimal the next few days. The series
of systems will eventually take its toll with the landslide
threat increasing this weekend into early next week. Felton

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...None.
PZ...Small Craft Advisory until 10 PM PST this evening for Coastal
     Waters From Cape Flattery To James Island 10 To 60 Nm-
     Coastal Waters From James Island To Point Grenville 10 To
     60 Nm-Coastal Waters From Point Grenville To Cape
     Shoalwater 10 To 60 Nm.

&&

$$