643
FXUS66 KSEW 140456
AFDSEW

Area Forecast Discussion
National Weather Service Seattle WA
956 PM PDT Mon Oct 13 2025

.UPDATE...Mostly clear skies with easing winds this evening. A
good combination for a brisk start to the day Tuesday. Forecast on
track this evening. No forecast update. Previous discussion
follows with updated aviation and marine sections. Felton

&&

.SYNOPSIS...Weak high pressure building into the region, combined
with offshore flow, and will bring cool and dry conditions to the
western Washington on Tuesday and Wednesday. A weak system will
bring the return of showers to the area Thursday into Friday with
a stronger, wetter system expected to move into the area this
weekend.

.SHORT TERM /TODAY THROUGH WEDNESDAY/...The upper low that
brought showers and mountain snow on Sunday has now shifted to our
south, with dry northerly flow currently over western WA. Gusty
NE Fraser River outflow winds will ease across western Whatcom and
San Juan counties this afternoon. The focus now shifts to
overnight lows as they will be quite chilly. With clear skies and
lighter winds, Tuesday`s lows will drop into the lower to mid 30s
- mainly interior areas away from the sound. This will be the
coolest of the season so far and a Frost Advisory is in effect.
Wednesday morning temps will also be cool but the flow will turn
onshore during the day. Expect highs around 60 with clear skies
otherwise. 33

.LONG TERM /THURSDAY THROUGH SUNDAY/...Weak high pressure will
nudge inland on Thursday but some warm frontal precip may clip the
coast for a chance of light rain. A weak cold front will follow
Thursday night but overall QPF is light with just a few
hundredths. Showers will linger into Friday with ongoing onshore
flow. A wetter Pacific storm system is slated to move inland this
weekend (mainly on Sunday) for more rain, mountain snow, and
locally windy conditions. 33

&&

.AVIATION...Upper level ridge nosing into British Columbia with
upper level low over Central California creating northeasterly
flow aloft over the area. Northerly flow in the lower levels.

Mostly clear skies through Tuesday. Patchy valley fog Tuesday
morning from 13z-16z.

KSEA...Mostly clear skies through Tuesday. North northeast wind 10
to 15 knots easing to 6 to 10 knots around 12z. Felton

.MARINE...High pressure will build over area waters later tonight through
Thursday, bringing light onshore flow and calmer conditions over
the waters starting Tuesday morning. The next impactful system
will arrive towards the end of the week and into the weekend, with
potential for widespread Small Craft winds over the outer and
inner waters.

Combined seas remaining around 4 to 6 feet through midweek before
potentially rising above 10 ft towards the weekend.

15/Felton

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...Frost Advisory from 2 AM to 8 AM PDT Tuesday for Downtown
     Everett / Marysville Area-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-Foothills and Valleys of Thurston
     and Lewis Counties-Foothills and Valleys of the North
     Cascades-Lowlands of Lewis and Southern Thurston Counties-
     Lowlands of Western Skagit and Northwestern Snohomish
     Counties-Middle Chehalis River Valley-Olympia and Southern
     Puget Sound-Southern Hood Canal.

PZ...None.
&&

$$