Brier Weather Station
Latitude N 47° 46' 49" Longitude W 122° 16' 48" Elevation 341 ft
224
FXUS66 KSEW 311632
AFDSEW
Area Forecast Discussion
National Weather Service Seattle WA
932 AM PDT Mon Aug 31 2026
.SYNOPSIS...
Weak upper ridging over the Pacific Northwest will
bring dry weather to begin the week. A stronger early season
system Wednesday into Thursday results in more widespread
rainfall and gusty winds. The deep upper low lingers over the
Pacific Northwest into next weekend for cooler conditions.
&&
.SHORT TERM /TODAY THROUGH WEDNESDAY/...
Mainly clear skies early this morning across Western Washington
with weak upper ridging in place. Localized fog and low stratus
may develop early this morning, otherwise, high clouds will be
around at times today. Dry conditions continue through tonight.
Highs today peak in the 70s for most areas.
Troughing begins to approach the Pacific Northwest offshore on
Tuesday with increasing clouds. Although Tuesday is expected to
be predominantly dry into the afternoon for most locations, a
few showers begin to increase in the afternoon, with a 10%
probability of thunderstorms in the Cascades late due to
increasing south flow aloft.
A very deep, anomalous early season upper low moves southwards
out of the NE Pacific into the offshore waters on Wednesday.
This system will bring widespread rain into Western Washington
Wednesday through Thursday. The heaviest rainfall is expected
over the Olympic Peninsula given the vicinity of the upper low,
however, measurable rainfall is expected for all locations. In
addition to the rain, gusty winds are expected, especially for
early September standards, as noted on the ECMWF EFI. NBM
highlights the probability for wind gusts exceeding 40 MPH
between 30 to 70% for the immediate coast, Whidbey Island, San
Juan Islands, and western Whatcom County. Elsewhere, gusts of 25
to 35 MPH are forecast at this time. Given the vegetation on
trees, early season wind impacts such as blown down tree limbs
and isolated power outages can`t be ruled out. Temperatures drop
into the 60s on Wednesday due to the presence of the stronger
system by midweek.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
Unsettled conditions continue into Thursday as the upper low
placement remains offshore of Washington and Oregon. Showers
will remain a threat Thursday. Thunderstorm probabilities also
increase towards 15 to 30% on Thursday, and will need to monitor
the lightning threat in heavier showers. Although winds will be
lighter on Thursday, continued south winds remain locally
breezy. Ensembles are in good agreement of troughing over Oregon
and Washington Friday into Saturday. The rain threat is
expected to slowly diminish during this period, but wrap around
moisture may still bring continued precipitation to some areas.
Uncertainty begins to increase by late weekend, however,
ensembles do begin to show troughing slowly moving eastwards
heading into next week. JD
&&
.AVIATION...
West to southwesterly flow will continue as a weak upper level
ridge departs to the east. A few terminals remain under
localized IFR/LIFR cigs due to low clouds and fog, but these
conditions should burn away before 17-18Z this morning. VFR
conditions continue through the rest of the day with high clouds
overhead. Low stratus is forecast to build along the coast late
this evening and build inland early Tuesday morning. Currently
the locations most likely to see stratus include OLM and PWT,
but there is a 10-15% chance it could reach all the way to SEA.
PAE may also see localized fog once again. Winds today will
remain N, becoming 5-10 kt this afternoon. Winds then become
light before switching to S on Tuesday.
KSEA...VFR conditions continue through the TAF period. Winds
increase to 5-10 kt this afternoon, but become variable under 5
kt tonight as they switch to the south. There is a 10-15% chc of
IFR or lower ceilings after 12Z Tue.
62
&&
.MARINE...
High pressure will remain offshore over the coastal
waters and into Tuesday. Benign conditions with light winds will
continue into Tuesday as a weak system bypasses to the north. A
significant pattern change remains on track midweek with a
large-scale low pressure system and front dropping down from the
Gulf of Alaska Wednesday into Thursday. Confidence has remained
persistent with the 60-80% likelihood for most of the coastal
waters, the east Strait of Juan de Fuca and Admiralty Inlet
waters over the past 3 days with the model data. A gale watch
was issued for these areas for the day Wednesday as sustained
winds of 25-35 kt remain likely, and some potential for a couple
gusts to 40 kt. Remaining waters will likely see some impact
from gusty winds out of the south and southeast with this
system, though the threat of gale gusts is much less (for Puget
Sound/Admiralty, and the central/west Strait of Juan de Fuca
sections). The system will also bring several rounds of rain and
a slight chance of thunderstorms for the coastal waters on
Wednesday. The system will move out again on Thursday, and winds
will decrease significantly going into the weekend.
Seas will remain at 3-6 ft through late Tuesday. The midweek system
will bring seas around 8-11 ft Wednesday into Thursday, but will
drop back to 4-6 ft Friday into next weekend.
HPR
&&
.FIRE WEATHER...
A brief warming and drying trend will occur today under weak
high pressure. Relative humidity minimums in the central and
southern Washington Cascades will decrease to around 25 to 30
percent this afternoon. Finer, flashier fuels will be more apt
to respond to the dip in RH. More clouds arrive ahead of the
stronger system for only partly sunny skies on Tuesday. By late
Tuesday night into Wednesday, the stronger system arrives for
widespread rain, windy conditions, and slight chances for
thunderstorms.
21
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...None.
PZ...Gale Watch from Tuesday evening through Wednesday evening for
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-East
Entrance U.S. Waters Strait Of Juan De Fuca-Northern
Inland Waters Including The San Juan Islands.
&&
$$
NWS SEW Office Area Forecast Discussion