969
FXUS66 KSEW 300332
AFDSEW

Area Forecast Discussion
National Weather Service Seattle WA
832 PM PDT Mon Sep 29 2025

.UPDATE...Rain and showers linger as a post-frontal regime takes
hold across W WA. Showers will decrease tonight as the associated
front marches east and away from the region. However, the next
disturbance is right on its heels and another round a widespread
rain and gusty winds enters on Tuesday. Overnight lows are to
range between the upper 40s to lower 50s.


&&

.SYNOPSIS...Another frontal system will bring rain and breezy to
locally windy conditions to Western Washington later Tuesday into
Wednesday. An upper level trough over the area will maintain
unsettled conditions into Thursday. A weak upper level ridge will
lead to somewhat drier conditions toward the end of the week.

&&

.SHORT TERM /TONIGHT THROUGH THURSDAY/...Light rain continues to
gradually spread inland this afternoon as a weak front pushes
onshore. A few post-frontal showers will continue into this evening
before the area briefly dries out toward Tuesday morning. A stronger
system will bring rain back to the coast by midday Tuesday spreading
into Puget Sound by late afternoon or early evening. The front will
move onshore Tuesday night with a trailing vertically stacked trough
parking itself offshore Wednesday into Thursday. The Olympic
Peninsula will be the focal point for the first significant precip
event of the autumn season with QPF totals of up to 4 to 7 inches of
rain in the southwest Olympics by Thursday. This will be the first
noteworthy system of the season with windy conditions expected coast
and north interior and breezy elsewhere. Unsettled conditions will
persist into Thursday as a series of upper level disturbances
rotating around the upper trough keep showers going. Temperatures
through the short term will run near or a little below normal.

.LONG TERM /FRIDAY THROUGH MONDAY/...A majority of the ensembles
are pointing toward a drier trend this weekend into early next week
as a ridge builds well offshore. There`s still uncertainty with
regard to how quickly the transition will occur. Current forecasts
preserve low end shower chances lingering into Friday or early
Saturday as a couple of systems moving through British Columbia
brush the area. Confidence in drier conditions increases for the
beginning of next week with temperatures trending a little below
average and some crisp autumn nights in the offing. 27

&&

.AVIATION...Southwesterly flow aloft will will persist as an upper
level troughing dominates over the region. The front has not moved
inland and will to slowly move eastward this afternoon. Rain and
elevated south/southeasterly winds will accompany the frontal
passage. Isolated thunderstorms are possible, mainly along the
coast, but confidence is night high enough to include in any TAF.
Ceilings are a bit of a mixed bag, varying from VFR to IFR in some
locations. Visibility is also being limited in heavier rain. Expect
ceilings to remain in the MVFR to low-end VFR (or IFR along the
coast) through the afternoon and temporarily improve to VFR this
evening into the early overnight hours. Light winds and  moisture
should allow ceilings to return to MVFR by early Tuesday morning,
with some areas of fog possible. ANother front will approach the
coast Tuesday, keeping low clouds along the coast and increasing
mid/high level clouds across the interior though remaining VFR.
Winds will increase area wide on Tuesday, reaching 10- 15 kt with
gusts up to 25 kt across the interior by Tuesday afternoon, with
higher winds along the coast.

KSEA...VFR conditions continue early this afternoon with scattered
low clouds in rain. A few periods of MVFR are possible in heavier
rain, before ceilings improve more solidly to VFR this evening.
With southeasterly winds decreasing overnight, areas of fog are
possible around the terminal and may limit visibility between around
13-17Z Tuesday morning. A return to VFR conditions is expected after
the fog lifts Tuesday. Southerly winds will also begin to increase
on Tuesday, reaching 10-15 kt with gusts up to 20 kt by Tuesday
afternoon.

62

&&


.AVIATION...Showers exiting this evening with moist SW flow aloft.
Isolated thunderstorms are possible, mainly along the coast, but
confidence is not high enough to include in any TAF. Ceilings are
a bit of a mixed bag, varying from VFR to IFR in some locations.
Visibility is also being limited in heavier rain. Expect ceilings
to remain in the MVFR to low-end VFR (or IFR along the coast)
and temporarily improve to VFR during the early overnight hours.
Light winds and moisture should allow ceilings to return to MVFR
by early Tuesday morning, with some areas of fog possible. Another
front will approach the coast Tuesday, keeping low clouds along
the coast and increasing mid/high level clouds across the interior
though remaining VFR. Winds will increase area wide on Tuesday,
reaching 10- 15 kt with gusts up to 25 kt across the interior by
Tuesday afternoon, with higher winds along the coast.

KSEA...A few periods of MVFR are possible in heavier rain, before
ceilings improve more solidly to VFR this evening. With
southeasterly winds decreasing overnight, areas of fog are
possible around the terminal and may limit visibility between
around 13-17Z Tuesday morning. A return to VFR conditions is
expected after the fog lifts Tuesday. Southerly winds will also
begin to increase on Tuesday, reaching 10-15 kt with gusts up to
20 kt by Tuesday afternoon.

62

&&

.MARINE...This morning`s cold front has just passed the
Washington coastline this afternoon and will continue to slowly
drift inland through the rest of the day. Winds across the area
are 20 kt or less and remain like so through the rest of the day.

Winds will begin to increase after midnight on Tuesday as another
frontal system approaches the area. This front, which will be
stronger, will move through the coastal waters Tuesday night.
Winds will increase to gale force across the coastal waters, the
East Strait of Juan de Fuca, and portions of the Northern Inland
Waters. Elsewhere, Small Craft Advisory winds are expected with the
exception of the Central Strait, which should remain largely
sheltered from the southeasterly winds. Winds will remain elevated
across the area waters as the low pressure center remains just
offshore. The low looks to weaken and move inland Thursday into
Friday, allowing winds to decrease. High pressure will then build
back across the northeastern Pacific for the end of the week.
Additional systems may move through the area waters this weekend.

Seas are still hovering around 10-12 ft this afternoon, but should
ease to around 8-9 ft tonight. Waves will then rapidly increase to
around 13-16 ft tomorrow, mostly southerly waves with the winds,
building further to 15-19 ft on Wednesday, becoming westerly as
waves generated by the low pressure system reach the coast. Waves
will ease on Thursday below 10 ft, remaining around 6-8 ft going
into the weekend.

62


&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...Wind Advisory from 2 PM to 11 PM PDT Tuesday for San Juan County.

     High Surf Advisory from 11 AM Tuesday to 5 AM PDT Thursday for
     Grays Harbor County Coast-Northern Washington Coast.

     Wind Advisory from 11 AM to 8 PM PDT Tuesday for Grays Harbor
     County Coast-Northern Washington Coast.

PZ...Small Craft Advisory from 11 AM Tuesday to 5 AM PDT Wednesday
     for Grays Harbor Bar-Puget Sound and Hood Canal.

     Small Craft Advisory from 5 AM Tuesday to 5 AM PDT Wednesday for
     Admiralty Inlet-West Entrance U.S. Waters Strait Of Juan De
     Fuca.

     Gale Warning from 5 AM Tuesday to 5 AM PDT Wednesday for East
     Entrance U.S. Waters Strait Of Juan De Fuca-Northern Inland
     Waters Including The San Juan Islands.

     Small Craft Advisory until 2 AM PDT Tuesday 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.

     Gale Warning from 2 AM to 11 PM PDT Tuesday 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.

&&

$$