425
FXUS66 KSEW 042223
AFDSEW

Area Forecast Discussion
National Weather Service Seattle WA
223 PM PST Tue Nov 4 2025

.SYNOPSIS...
A warm front will be lifting into the region late tonight,
bringing rains and gusty winds as the center of the low passes
offshore. The trailing cold front will stall over western
Washington tomorrow before dissipating tomorrow night. An
atmospheric river will move in on Thursday for rain and windy
conditions lingering into Friday.

&&

.SHORT TERM /TODAY THROUGH THURSDAY NIGHT/...
Its been a cloudy but relatively dry day today, but that will
soon be coming to an end as the afternoon and evening
progresses. There`s a lot going on in the short term, so the
rest of this discussion will be broken out into key points on
the expected hazards.

Winds:

*Breezy to windy conditions will materialize tonight as a strong
 area of low pressure enters the offshore waters. The warm front
 will lift into the region late tonight. A wind advisory is
 still scheduled to go into effect for the Cascade Foothills.

*Another round of breezy conditions will develop with the next
 system arriving early Thursday morning, but the winds will be
 out of the south. Areas likely to receive the strongest winds
 are the coast, eastern Strait of Juan de Fuca and the northern
 inland waters. Winds will begin easing late Thursday night.

Rain:

*Between tonight and late Wednesday night, QPF expected will be
 between 2-3 inches in the Olympics and 1-2 in the Cascades.
 Lowland Puget Sound locations will receive around half to
 three quarters of an inch of rain.

*The system arriving Thursday into Friday will be slightly
 wetter for lowland locations, with mountain locations still
 receiving on the order of 2 to 3 inches.

Coastal Flooding and High Surf

*The coastal flood advisory has been upgraded to a coastal flood
 warning for the Pacific coast. Moderate to major coastal
 flooding is expected, along the coast, with tidal gauges in
 Westport and La Push showing water levels reaching 2 to 3 feet
 above ground level, due to higher astronomical tides.

*A High Surf Advisory has been issued for the coast beginning
 Thursday morning, lasting into late Thursday night for breaking
 waves of 20 to 25 feet. With higher astronomical tides still in
 the forecast, high surf can exacerbate coastal flooding
 impacts. Thursday should be taken just as seriously as
 Wednesday with the compounding effect of the high waves.

Winter Weather

*A winter weather advisory has been issued for the Cascades of
 Skagit and Whatcom counties, particularly affecting the higher
 elevations of Highway 20 where 4 to 8 inches of snow is
 possible. The Mount Baker area could receive 8 to 10 inches of
 new snow between Wednesday afternoon and Thursday morning.

&&

.LONG TERM /FRIDAY THROUGH MONDAY/...
Rain activity is likely to persist into Friday, but the trend
appears to indicate calmer weather over the weekend. The cluster
analysis shows that a ridge is favored for more quiescent
weather Saturday through Sunday morning. PoPs return to the
forecast Sunday for light shower activity across the area. Right
now, there appear to be no severe wind threats in the late week
and weekend time frame but this will be monitored.

21

&&

.AVIATION...
Majority of terminals VFR this afternoon, with the
exception of OLM and CLM, where stubborn low clouds have kept
ceilings MVFR. Improvement is expected by this evening. A frontal
system will bring widespread rain to the area starting this evening
(after 02z, continuing throughout the day on Wednesday. There is a
small chance of thunder after 17z; latest guidance suggest the
highest chances (30-35%) are along the coast, while the interior
terminals have a 10-25% chance, with the highest chances in the
southern interior. Ceilings will gradually lower overnight (after
08z-09z) to MVFR and will prevail throughout the remainder of the
TAF. Southeasterly winds will increase this afternoon and evening.
Latest high-res guidance suggests sustained winds of 10-15 kt and
gusts of 30-40 kt, peaking between 05z-10z. Strong winds continue
into Wednesday and will persist throughout the day, becoming
southerly-southwesterly in the afternoon.

KSEA...VFR at the terminal this afternoon. However, conditions are
expected to deteriorate to MVFR overnight as a frontal system pushes
through. MVFR ceilings expected to prevail throughout the TAF
period. Latest guidance suggests rain will start impacting the
terminal after 02z and will continue throughout Wednesday. There is
a 10-15% chance of thunder, however confidence is low. Strong
southeasterly winds are expected this evening. Latest high-res
guidance suggests sustained winds of 10-15 kt and gusts of 30-40 kt,
with the highest winds peaking between 05z-09z. Winds will decrease
slightly after 09z, however still gusting to 20-30 kt. South-
southwesterly winds Wednesday afternoon/evening at speeds of 10-15
kt and gusting to 30-35 kt.

29
&&

.MARINE...
A warm front will lift into the area waters tonight with gale
force winds over the coastal waters and Strait of Juan de Fuca.
Wind directions will be offshore due to the deeper low pressure
approaching the outer waters and a strong offshore gradient.
The cold front will catch up into tomorrow for a continuation of
the breezy conditions, though the winds will become more
southerly by tomorrow afternoon. Primary marine hazards in the
short term will be steep seas, with wave heights in excess of 15
to 20 feet, peaking on Thursday at 20 to 25 feet. Hazardous
marine conditions are likely through the late week period, with
additional hazards likely to be posted for Thursday in
subsequent forecasts.

21

&&

.HYDROLOGY...
Predicted rainfall totals over the south slopes of
the Olympics from Wednesday night through Friday morning
continue to be in the 2.5 to 4 inches range with locally higher
amounts possible. The Skokomish river will already be near
action stage from the rain Tuesday night through Wednesday. This
additional rainfall has a good chance of causing the river to
go above flood stage as early as Thursday afternoon. A flood
watch will continue for Mason county for Thursday afternoon
through Saturday morning.

Rainfall amounts in the Cascades forecast to be a little less,
in the 1.5 to 3 inch range. West southwesterly flow aloft this will
focus some of the heavier rain in the Cascades of Northern King
and Snohomish county. No flooding is predicted at this time for
rivers flowing off the Cascades. The Snoqualmie, Skykomish and
Snohomish could get into action stage with the heavier rain in
the headwaters.

Felton/Mazurkiewicz

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...Winter Weather Advisory from 4 PM Wednesday to 10 AM PST
     Friday for Cascades of Whatcom and Skagit Counties.

     Wind Advisory from 6 PM this evening to 4 AM PST Wednesday for
     Foothills and Valleys of Central King County-Foothills
     and Valleys of Pierce and Southern King Counties-
     Foothills and Valleys of Snohomish and Northern King
     Counties.

     Flood Watch from Thursday afternoon through Saturday morning
     for Foothills of the Western and Southern Olympic
     Peninsula-Middle Chehalis River Valley-Olympia and
     Southern Puget Sound-Olympics-Southern Hood Canal-Willapa
     and Black Hills.

     Coastal Flood Warning from 7 AM Wednesday to 10 PM PST
     Thursday for Grays Harbor County Coast-Northern
     Washington Coast.

     High Surf Advisory from 4 AM to 7 PM PST Thursday for Grays
     Harbor County Coast-Northern Washington Coast.

PZ...Small Craft Advisory from midnight tonight to 4 PM PST
     Wednesday for Grays Harbor Bar.

     Gale Warning until 6 PM PST Wednesday for Central U.S. Waters
     Strait Of Juan De Fuca-West Entrance U.S. Waters Strait
     Of Juan De Fuca.

     Gale Warning from 6 PM this evening to 4 PM PST Wednesday for
     East Entrance U.S. Waters Strait Of Juan De Fuca.

     Small Craft Advisory from 10 PM this evening to 10 PM PST
     Wednesday for Admiralty Inlet-Northern Inland Waters
     Including The San Juan Islands.

     Gale Warning from 6 PM this evening to 6 PM PST Wednesday 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.

     Small Craft Advisory until 6 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.

&&

$$