447
FXUS66 KSEW 111604
AFDSEW

Area Forecast Discussion
National Weather Service Seattle WA
904 AM PDT Sat Oct 11 2025

.SYNOPSIS...Cool and unsettled conditions continue across
Western Washington this weekend and linger into early next week.
A system moving southward from British Columbia Sunday will
bring the first noteworthy high elevation snow of the season.
Drier conditions will return toward the middle of next week as
high pressure rebuilds over the region, followed by typical
autumnal conditions later next week.

&&

.SHORT TERM /TODAY THROUGH MONDAY/...A cooler air mass today with
showers over the area. Highs are only in the mid to upper 50s.
Short term trends are on track. 33

Previous discussion...Showers remain scattered across Western
Washington early this morning with a few clusters of enhanced
activity in the onshore flow around the approaching upper trough.
Expect lingering showers in the Cascades today and tonight, but a
break in between disturbances is likely. However, conditions
remain cool and cloudy even if drier. An upper level shortwave
moving southward through British Columbia will then bring another
wave of precipitation back into Washington from the north.

This system will also bring snow levels lowering from around
4000-6000 feet initially Sunday, down to 2500 ft or so in the
North Cascades. NBM continues to highlight 60-75% chance of 8
inches or more above 5000 feet over the northern portions of the
Cascades, and the winter weather advisory remains in effect to
reflect the potential impacts from this early season snow at the
higher mountain elevations. Snow levels will remain a little
higher across this southern portions of the Washington Cascades.
This will likely result in and inch or two at Stevens Pass and
little to no accumulation down at Snoqualmie (though expect
rain/snow mix at times late Sunday). Additional snow
accumulations are expected at Paradise at Mt Rainier, where
latest webcam imagery suggests some flakes are already in the
air as the temperature has fallen to around the freezing mark.
The bottom line is that those who plan to head into the higher
mountain elevations this weekend should be prepared to encounter
snow and cold conditions and closely monitor the weather
forecast in the next few days.                      12

.LONG TERM /TUESDAY THROUGH FRIDAY/...Ensemble guidance
continues to favor the upper low tracking south into California.
This begins to push the precipitation chances away from the
region, bringing a drier trend and decreasing cloud cover. This
will bring some elevated concern for morning frost Monday and
Tuesday as clearing skies and light winds yield efficient
cooling and temperatures may reach the mid to upper 30s for the
sheltered interior locations away from the water. After a few
dry days, guidance favors a return of a more active pattern, and
associated precipitation chances, late in the week.    12

&&

.AVIATION...Increasing northwesterly flow aloft through today as an
upper level trough deepens over the Pacific Northwest into Sunday.
Generally MVFR/IFR cigs this morning with abundant moisture at the
surface. Showers will continue at times today with an unsettled
weather pattern, a convergence zone may also develop this evening
into tonight in central Puget Sound. Predominantly MVFR cigs
expected this afternoon and continuing into tonight. VFR may occur
briefly at times, particularly for the coast. Otherwise, brief vsby
reductions also possible with showers. W/SW winds will continue into
tonight.

KSEA...MVFR/IFR cigs this morning. MVFR cigs are expected for the
majority of today. Brief VFR cigs may occur tonight, but primarily
MVFR cigs into Sunday morning. Showers will be around at times as
well, with a convergence zone potentially developing N of the
terminal this evening. Brief vsby reductions towards 3-5 SM are
possible in showers. S/SW winds at the surface, ranging 7 to 12 kts
through tonight. JD

&&

.MARINE...High pressure will briefly build in over the coastal
waters today as the trough along the coast pushes inland this
morning. Winds will begin to increase over the coastal waters later
this morning, mostly to Small Craft Advisory criteria, except to
gale force in the outer coastal waters north of Point Grenville.
Winds will increase a bit through the Strait of Juan de Fuca as
well, but should remain below advisory criteria. Some gusts to 20-25
kt cannot be ruled out, however, this afternoon through tonight.

Winds will begin to ease early Sunday morning, through there will
not be much of a break. A low pressure system will begin to form
along the southern coast of Vancouver Island Sunday evening and move
southward along the coast on Monday. Winds will begin to turn
offshore by around midnight Monday morning, with Small Craft
Advisory winds once again through the outer coastal waters on
Monday. Northeasterly winds look to also reach advisory level
through the Northern Inland Waters and portions of the East and
Central Strait of Juan de Fuca. Winds look to ease Monday night as
broad high pressure begins to build back in for much of the rest of
next week.

Seas currently around 6 ft this morning will rise to around 12-15 ft
by tonight. Seas will be steep with a dominant period of around 10
to 11 seconds. Seas will gradually subside Sunday, becoming around 5
to 8 ft by Monday evening.

62

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...Winter Weather Advisory from 5 AM Sunday to 5 AM PDT Monday for
     Cascades of Whatcom and Skagit Counties.

PZ...Small Craft Advisory from 8 PM this evening to 5 PM PDT Sunday
     for Grays Harbor Bar.

     Small Craft Advisory from 5 PM this afternoon to 5 PM PDT Sunday
     for Coastal Waters From Cape Flattery To James Island Out
     10 Nm-Coastal Waters From James Island To Point Grenville
     Out 10 Nm-Coastal Waters From Point Grenville To Cape
     Shoalwater Out 10 Nm.

     Gale Warning until 2 PM PDT Sunday 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.

     Small Craft Advisory until 5 PM PDT Sunday for Coastal Waters
     From Point Grenville To Cape Shoalwater 10 To 60 Nm.

&&

$$