Brier Weather Station
Latitude N 47° 46' 49" Longitude W 122° 16' 48" Elevation 341 ft
164
FXUS66 KSEW 292213 CCA
AFDSEW
Area Forecast Discussion...CORRECTED
National Weather Service Seattle WA
313 PM PDT Tue Sep 29 2026
.SYNOPSIS...A frontal system will move out of Western Washington
into this evening. High pressure builds aloft over the Pacific
Northwest Thursday and Friday, with just a slight chance of
precipitation. The upper ridge further builds over the weekend
for drier, warmer conditions.
&&
.SHORT TERM /TODAY THROUGH THURSDAY NIGHT/...The frontal system
continues to move across Puget Sound this afternoon, with
lingering light rain into tonight. Weak convergence over
Snohomish and King Counties will also subside tonight.
Impressive QPF amounts the last 24 hours over the western
slopes of the Olympics and North Cascades, with 2-3.5 inches of
rainfall over these areas. Significantly less rain from Seattle
southwards due to shadowing and the weakening front. Southerly
winds will also subside into this evening.
Drier conditions develop Wednesday into Thursday as high
pressure begins to build into the Pacific Northwest. Morning
stratus and localized areas of fog due to residual moisture will
clear for some sunshine during the afternoon. A system will
weaken along the northern periphery of the ridge late Thursday,
resulting in a slight uptick in rainfall potential beginning
later Thursday into Thursday night, however any QPF amounts are
expected to remain light, mainly focused on areas near the BC
border. Highs mainly in the low to mid 60s Wednesday and
Thursday.
&&
.LONG TERM /FRIDAY THROUGH MONDAY/...The aforementioned
weakening system may continue to bring light rain along the
northern tier, mainly North Cascades on Friday, but
predominantly dry conditions are expected. Ensembles are in good
agreement in the upper ridge building further over the Western
US this weekend, with dry conditions and warming temperatures
over Western Washington. Dry conditions look to continue into
early next week, although an increase in onshore flow may result
in slightly cooler temperatures by Monday. JD
&&
.AVIATION...Strong west to northwesterly flow will persist
aloft today and into Wednesday. A frontal system continues to
make its way across western Washington this afternoon, bringing
rain and breezy winds to the area. Southwesterly surface winds
are generally persisting between 10-15 kt with gusts to 20-25
kt this afternoon. Winds will ease into this evening as the
front pulls away from the area and the wind direction shifts
more to the north/northeast in its wake. Expect winds to subside
to 5-10 kt between 03-06Z and for some locations to go light and
variable overnight.
There is a wide variation in cigs across the terminals this
afternoon, with most terminals reporting either MVFR to IFR
conditions. Cigs may continue to trend downward in rain as this
frontal system works its way through the area. A convergence zone
in the wake of the front is likely to develop across Snohomish
County between 00-03Z. While some terminals may improve to high-
end MVFR to low- end VFR this evening into early tonight,
lingering low- level moisture from will likely bring another round
of widespread MVFR to IFR conditions to the area terminals
overnight into Wednesday morning.
KSEA...MVFR conditions this afternoon with a fair amount of rain
shadowing at the terminal. Brief reductions to IFR remain
possible in any rain. Cigs may briefly recover back to around
3000 ft tonight, but expect improvement to be short-lived as
another round of IFR to MVFR cigs are likely to develop at the
terminal between 12-14Z. Southwesterly winds between 10-15 kt
with gusts to 25 kt will ease towards 5-10 kt by this evening
and switch to the north/northeast between 02-05Z.
&&
.MARINE...Winds continue to subside this afternoon as a frontal
system makes its way through the area waters. Westerly winds
will increase to 25 kt along the central and eastern Strait of
Juan de Fuca this evening in the wake of the front. Seas
currently ranging between 7-10 ft will subside towards 6-8 ft by
tonight.
Onshore flow will diminish by early Wednesday. As such, seas
will also quickly subside to 4-6 ft around midday as the
frontal system gets further away from the coastal waters.
Surface high pressure building over the interior of British
Columbia and weak troughing just offshore will lead to the
development of some weak east/southeast flow on Thursday. A
thermally induced surface trough will begin to expand northward
along the coast by the weekend for northerly or weak offshore
flow across area waters. Seas will primarily persist between 3-6
ft.
&&
.FIRE WEATHER...Widespread wetting rains have been observed
over the Olympics, as well as the central and northern Cascades
the last 24 hours. Drier weather returns Wednesday, before a
weak system late Thursday into Friday brings a slight chance of
rain, mainly along the Olympics and North Cascades. A pronounced
upper ridge develops Saturday and Sunday resulting in drier
conditions, warmer temperatures, and a brief period of offshore
winds, particularly during the overnight and morning hours. JD
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...None.
PZ...Small Craft Advisory until 5 AM PDT Wednesday for Central U.S.
Waters Strait Of Juan De Fuca-East Entrance U.S. Waters
Strait Of Juan De Fuca.
Small Craft Advisory until 5 PM PDT this afternoon for
Admiralty Inlet-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-Northern Inland Waters Including The
San Juan Islands-Puget Sound and Hood Canal.
&&
$$
NWS SEW Office Area Forecast Discussion