Brier Weather Station
Latitude N 47° 46' 49" Longitude W 122° 16' 48" Elevation 341 ft
829
FXUS66 KSEW 270325
AFDSEW
Area Forecast Discussion
National Weather Service Seattle WA
825 PM PDT Mon Oct 26 2026
.SYNOPSIS...
Troughing will persist over the Pacific Northwest
into Tuesday for unsettled conditions and periodic showers. A
frontal system on Wednesday brings increasing steadier rainfall
and mountain snow. An upper low then lingers over Western
Washington into late week for unsettled weather and cooler
temperatures.
&&
.SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/...
The weather system that was offshore continues to move inland
this evening with a cold front draped across Puget Sound.
Showers will continue at times into Tuesday with troughing
persistent over the Pacific Northwest. High temperatures range
in the mid to upper 50s on Tuesday.
Another frontal system moves southwards from British Columbia
Tuesday evening through Wednesday, resulting in the return of
steadier rainfall for the lowlands, especially Tuesday night.
Southwest winds also increase for portions of southern and
central Puget Sound late Tuesday, peaking between 20 to 30 MPH
from Seattle to Tacoma and westwards towards Shelton. The most
impactful aspect to this system will be the first widespread
mountain snow event for the Cascades and Olympics this season.
Snow levels initially around 4000 to 4500 feet fall to 3000 to
3500 feet by Wednesday morning, resulting in snow for the higher
elevation Cascade Passes. At this time, the heaviest snowfall
is forecast for White Pass and Paradise (6 to 12 inches, with
localized amounts to 15 inches around Paradise). Snowfall
accumulations of 4 to 8 inches are anticipated for Stevens and
Rainy Pass, with up to 3 inches at Snoqualmie Pass due to
slightly higher snow levels above 3000 feet. For this reason, a
Winter Weather Advisory has been issued for the Cascades, those
traveling will want to be aware of the incoming snow, and check
WSDOT for updates.
Showers then continue through Wednesday night as the weather
system slowly moves southwards along the offshore waters.
Temperatures will be slightly cooler Wednesday with highs only
in the low to mid 50s.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
Ensembles are consistent in the upper low lingering over
Western Washington through at least Friday, which results in
continued unsettled conditions with showers at times. Snow
levels fluctuate between 2500 to 4000 feet Thursday and Friday,
with light snow accumulations at times for the Cascades and
Olympics. Uncertainty increases next weekend in regards to how
quickly the upper trough exits the Pacific Northwest. At this
time, the trend is for a slow drying trend over the weekend into
early next week. Temperatures will become cooler over the
weekend, and will need to monitor the threat for frost and
freeze conditions Saturday into early next week. JD
&&
.AVIATION...
Flow aloft will transition to northwesterly as a low continues
to push inland across northern Oregon. Surface winds remain light
and variable this evening at generally 5 kt or less. Expect a
gradual transition to the southwest for the majority of the interior
terminals.
Scattered shower activity continues across the area this evening.
Conditions are mainly VFR at the majority of the area TAF sites
though with ample low level moisture and a switch back to onshore
flow, expect MVFR, to localized IFR, conditions to develop tonight
into Tuesday.
KSEA...VFR conditions are expected to persist this evening, with SW
winds between 3-6 kt. Conditions will drop back down to MVFR
overnight into early Tuesday, with latest probabilistic guidance
hinting at roughly a 15% chance of conditions becoming IFR by 12Z.
SW wind will increase to 7-12 kt on Tuesday afternoon.
14/41
&&
.MARINE...
A weakening surface low will continue to push inland into
northern Oregon this evening, bringing a return of onshore flow
to the area. Northwesterly winds along the outer coastal waters
will become breezy early Tuesday into Wednesday, with wind
gusts approaching 25 kt at times. Another frontal system will
move into the waters Tuesday night into Wednesday, increasing
winds and seas across the area. Increasing onshore flow will
bring a push of small craft westerly winds to the central and
eastern Strait Tuesday afternoon and evening. Southerly winds
will also pick up along the Puget Sound waters Tuesday night,
with latest guidance highlighting a 60-80% chance of gusts
exceeding small craft criteria.
Winds will ease again across the area waters on Wednesday as the
accompanying surface low drops into the area and tracks southward
along the coastal waters. This low will allow for flow to turn
back offshore, with offshore flow persisting the second part of
the week.
Seas between 3-6 ft will increase to 6-8 ft on Tuesday. Seas
will persist at 6-8 ft into Wednesday, before slowly subsiding
back to 4-6 ft on Thursday and persisting at this range into the
weekend.
14
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...Winter Weather Advisory from 5 PM Tuesday to 5 PM PDT
Wednesday for Cascades of Pierce and Lewis Counties-
Cascades of Snohomish and Northern King Counties-Cascades
of Southern King County-Cascades of Whatcom and Skagit
Counties.
PZ...Small Craft Advisory from 5 AM Tuesday to 5 AM PDT Wednesday
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.
&&
$$
NWS SEW Office Area Forecast Discussion