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FXUS66 KSEW 032235
AFDSEW

Area Forecast Discussion
National Weather Service Seattle WA
235 PM PST Wed Dec 3 2025

.SYNOPSIS...
A very active week ahead with a parade of weather systems
keeping conditions warm, wet, and windy from Thursday and
beyond. A more significant atmospheric river system event looks
to set up early next week with the potential for flooding.
Coastal flooding impacts will be possible Friday into early next
week but look to remain mostly minor.

&&

.SHORT TERM /TODAY THROUGH FRIDAY NIGHT/...
Cool, cloudy and mostly dry conditions will continue through
this evening. Temperatures right around 45 degrees across the
area will drop a bit into the upper 30s to low 40s tonight.
There could be some isolated patchy fog given the light winds
that will continue tonight. A frontal system will move across
the area on Thursday that will bring a decent push of rainfall
across the entire area. Up to half an inch of rainfall across
most of the lowlands and over an inch in the mountains will be
possible on Thursday. The associated surface low is pretty weak so
while north/northwesterly winds return across the area, they
will remain fairly weak. Highs in the mid 40s.

Flow turns westerly aloft allowing for the next frontal system
to move across the area Thursday night into Friday. This will
permit a more significant round of rainfall, with a couple of
inches of rain possible across the mountains, around an inch
along the coast, and lesser amounts through the interior. Winds
will increase across the interior, but remain below advisory
thresholds, with peak gusts in the 25-35 mph range. This will
also be a warmer system, with highs in low to mid 50s and snow
levels rising to around 5000-6000 ft.

Tide levels will increase Thursday and Friday across the area.
Fairly minor impacts are expected on Thursday for the coast,
with the potential for more significant impacts on Friday with a
higher tide, stronger onshore flow, and slightly larger waves.
The impacts, however, will not be as significant as the coast
saw in November. Tides peak on Friday along the coast then
through the interior this weekend, where additional minor
coastal flooding may be observed.

&&

.LONG TERM /SATURDAY THROUGH TUESDAY/...
Rain will continue into Saturday as the aforementioned system
moves through the area Friday night and substantial onshore flow
continues. Snow levels will briefly low Friday night into
Saturday back down to around 4000 ft, which may allow for a
brief but good shot of accumulating snow at Stevens Pass. There
is a 45% chance of seeing at least 6" of snow at the pass
through Saturday afternoon. Models are hinting at a bit of a
break in the precipitation Saturday evening until another,
albeit relatively weak and progressive, system moves through
Sunday. Snow levels will rise back up against 5000 ft. The
focus then turns towards Monday and trough the beginning of next
week as it`s looking likely that a significant atmospheric
river is going to take aim at western Washington. There remains
differences, mainly at how long duration this system is going to
persist over the area. There remains some uncertainty to exact
amounts, but on the order of several inches of rain are
possible across the entire area. More details about river
flooding are detailed in the hydrology section. Winds will
begin to pickup once again, and warmer temperatures will return,
back into the mid 50s. Snow levels rise back up to 6000 ft.

High tides will peak across the interior waters on Saturday, but
high tide levels will linger into the the beginning of next
week, with minor coastal flooding impacts possible across
portions of the entire Washington coastline through this time
period.

62

&&

.AVIATION...
Northwesterly flow aloft with a warm front approaching offshore.
Mixed bag of ceilings (VFR to IFR) continue as limited low
level flow keeps lower ceilings in place. Some minor improvement
to low end VFR is possible across portions of the interior this
afternoon. Conditions will start to lower overnight to MVFR/IFR
especially by Thursday morning as the aforementioned warm front
crosses the area. Rain could lower visibilities at times during
the morning to 4-6SM. Light and variable winds this afternoon
will start to take a southerly component around 06z and
remaining around 4 to 6 knots.

KSEA...VFR this afternoon will start to lower to MVFR later this
evening. An approaching warm front will spread rain showers late
tonight through early Thursday morning, possibly bringing vsbys
down at times. Conditions will lower to IFR (10z-17z) as the
rain comes in. Ceilings will remain MVFR/IFR through the
afternoon as lingering moisture keeps the ceilings low. Light
and variable winds will turn southerly overnight and remain
around 4 to 6 knots.

Mazurkiewicz

&&

.MARINE...
Surface high pressure will dissipate later this
evening allowing for a front to cross over the area waters with
no notable impact for the coastal waters.

A stronger front will approach the coastal waters on Friday, for
likely small craft advisory strength winds for the coastal
waters. A westerly push down the Strait of Juan De Fuca will
initially start off at small craft strength, but latest
guidance indicates the potential for gale strength gusts - will
be something to continue to monitor. Additional systems will
cross over the area waters over the weekend, with a much
stronger system crossing the area early next week, which could
yield headlines for all of the interior waters.

Combined seas 6 to 8 feet this afternoon will gradually build up
to 10 to 12 feet by Saturday. Seas will decrease below 10 feet
on Sunday but will build up above 10 feet by late Monday.

Mazurkiewicz

&&

.HYDROLOGY...
A series of wet weather systems forecast to reach the area will
eventually increase the threat of river flooding this weekend,
especially into the first half of next week. West to
northwesterly flow aloft with the system on Friday will put the
area of greatest precipitation in the North Central Washington
Cascades. Snow levels, at this time, will be rising over 5500 to
6000 feet.

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

There`s still a wide variance in the possible precipitation
amounts with an atmospheric river setting up through the first
part of next week. It is still within the realm of possibility
that we could have a widespread river flooding event on our
hands beginning next Tuesday/Wednesday, with multiple rivers
reaching minor and moderate flood stages. There is still so much
uncertainty with the exact flood levels and stages and this will
change over the next couple of days.

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

Felton/Mazurkiewicz

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...Coastal Flood Advisory from 9 AM to 3 PM PST Thursday for
     Grays Harbor County Coast.

     Coastal Flood Watch from Friday morning through Friday
     afternoon for Grays Harbor County Coast.

PZ...None.

&&

$$