488
FXUS66 KSEW 111028
AFDSEW

Area Forecast Discussion
National Weather Service Seattle WA
328 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/...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 /MONDAY NIGHT 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...Flow aloft becoming northwesterly today as an upper
level trough traverses the area. Ceilings are a mixed bag across the
area this morning. Scattered showers remain persistent,
particularly across the north interior and the Cascades.
Conditions will likely be up and down this morning, but models
have consensus on ceilings settling area-wide to MVFR as another
band of moisture and showers moves into to the area. Showers
will taper off tonight but ceilings remain MVFR or lower.
Convergence zone may be possible near KPAE this evening.

Winds southerly through the TAF period, with winds increasing to 8
to 15 kt this afternoon through tonight.

KSEA...VFR cigs this morning though gradually lowing to MVFR this
afternoon as showers return to the terminal. Southerly winds through
the TAF period around 5 kt this morning increasing to 8 to 12 kt
this afternoon through tonight.

62

&&

.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 from 8 AM this morning to 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 from 8 AM this morning to 5 PM PDT Sunday
     for Coastal Waters From Point Grenville To Cape
     Shoalwater 10 To 60 Nm.

&&

$$