Brier Weather Station
Latitude N 47° 46' 49" Longitude W 122° 16' 48" Elevation 341 ft
379
FXUS66 KSEW 011506
AFDSEW
Area Forecast Discussion
National Weather Service Seattle WA
806 AM PDT Tue Sep 1 2026
.SYNOPSIS...
A strong early season system brings rain and gusty
winds to Western Washington Wednesday into Thursday. The deep
upper low lingers over the Pacific Northwest into next weekend
for continued cooler and unsettled conditions.
&&
.SHORT TERM /TODAY THROUGH THURSDAY/...
Predominantly dry conditions today with a few showers
developing later today ahead of troughing developing offshore. A
mix of clouds and sunshine expected with highs in the 60s along
the coast and 70s for the interior.
A strong early season system will approach Western Washington
tonight with an associated front moving through on Wednesday.
This system will bring beneficial rain to the area, with the
highest rainfall amounts over the Olympic Peninsula, with some
areas exceeding 1-1.50" of rain into Thursday. The bulk of the
rainfall will move across Puget Sound Wednesday afternoon
through the evening. Rain will then continue at times on
Thursday with the deep upper low located offshore. In addition,
thunderstorm probabilities increase to 20 to 25% for most of the
area by Thursday afternoon, and embedded lightning can`t be
ruled out with heavier showers.
Winds may be the most impactful aspect to this system on
Wednesday given the continued full foliage on trees. At this
time, confidence is highest in impactful wind gusts (35-40 mph)
along the coast, San Juan Islands, and Whidbey Island. For this
reason, a Wind Advisory was issued for these areas on Wednesday,
primarily due to the continued foliage and increased risk for
downed tree limbs and isolated power outages. Will also need to
monitor western Whatcom and Skagit Counties, and the Port
Townsend area for further expansion of the Wind Advisory.
Elsewhere, wind gusts of 20 to 35 MPH are expected, and
localized power outages cannot be ruled out. Winds will peak for
most locations during the day on Wednesday before winds ease
Wednesday night into Thursday.
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...
The upper low remains situated over the Pacific Northwest
Friday into the weekend. This will result in cooler conditions
continuing for Western Washington. Lingering rain showers are
also expected to continue at times, although dry periods will
exist as well. Probability for thunderstorms remains around 10%
Friday and Saturday. Uncertainty begins to increase in ensembles
early next week in regards to the timing in which the troughing
begins to weaken and drift eastwards. However, a continued
troughing influence into Monday likely results in below normal
temperatures and the chance for precipitation over the area. JD
&&
.AVIATION...
South/southwesterly flow aloft continues with persistent upper
level troughing offshore. Ceilings under the marine layer remain
between MVFR and IFR, elsewhere VFR continues with high clouds
overhead. Marine layer clouds will raise to VFR later this
morning, through elsewhere mid-level clouds will increase this
afternoon as a warm front passes through the area and increases
moisture and chances for isolated showers this evening. Heavier
precipitation, associated with a cold front, will begin to
approach the coast between 09-12Z Wed this evening and slowly
move inland, not reaching the interior until after 18Z Wed-00Z
Thur. The heavier precip will likely also bring MVFR to IFR
ceilings once again and potential limitations in visibility.
South to southwesterly winds will continue to increase through
the morning, peaking this afternoon at around 8-15 kts with
gusts up to 20-25 kts possible through the afternoon and early
evening. Winds will then continue to pick up after 06-12Z Wed,
becoming up to 10-20 kt with gusts up to 25-35 kt along the
coast and through the north interior.
KSEA...A brief period of IFR conditions this morning under the
marine layer, but conditions should improve by 18Z this morning.
Otherwise VFR conditions prevail through the remainder of the
TAF period, with mid-level clouds increasing tonight.
Precipitation will not begin to arrive at the terminal until
around 15-18Z Wed. Southwesterly winds will increase this
afternoon to around 10-15 kt with gusts up to around 20-25 kt.
Winds ease slightly after 09Z Tue but will start to increase
once again after 18Z Tue.
62
&&
.MARINE...
High pressure will ease today before a stronger low
pressure system begins to approach the coastal waters late
tonight. South to southeasterly winds will begin to increase
this evening, with winds peaking during the day on Wednesday.
Likelihood remains high through the coastal waters (60-90% chc)
and through portions of the East Strait of Juan de Fuca, Strait
of Georgia, and Admiralty Inlet (50-70% chc) for seeing gale
force wind gusts through Wednesday evening. Forecast, however,
is having some difficulty latching on to these higher speeds,
favoring a zone average that could fall short. As such, left
Watch alone for the time being, but did emphasize Gale criteria
via gusts in forecast product. This sets the stage for potential
upgrade should the aforementioned 60-90 pct chance remain
intact. Elsewhere, winds will remain in or just under Small
Craft Advisory thresholds. As such, held off on these headlines
just yet and figured they`d best be served along with any
potential upgrade to the aforementioned Gale Watch.
The cold front will traverse the area waters Wednesday evening,
following which winds will begin to decrease. Additional
headlines may be needed into Thursday as southerly winds
remain elevated through the interior waters from Puget Sound to
the Northern Inland Waters. Winds greatly decrease area-wide by
Thursday afternoon as the low pressure system weakens and moves
southward into Oregon. Broad low pressure will remain over region
through the end of the week.
Chances for isolated thunderstorms will pose a threat to the area
waters Wednesday and Thursday, through probabilities are marginal
(10-20% chc).
Seas 4-6 ft increasing tonight to 7-9 ft before peaking late
Wednesday afternoon/early Wednesday evening at 9-12 ft. Seas return
to around 6-8 ft Friday into the weekend.
18/62
&&
.FIRE WEATHER...
Fire weather concerns remain low through the
next week. A stronger fall weather system will bring significant
rainfall starting early Wednesday, with wetting rains expected
area-wide. 1-2" will be possible along the Pacific Coast and
the Olympic Mountains. Rainfall may pose a minor threat to
highly sensitive and brand-new burn scars. Windy conditions are
also expected across the area with gusts ranging from 20 to 35
mph. The bulk of the rain will fall on Wednesday. Chances for
showers and isolated thunderstorms continue through the end of
the week, but the risk of new starts is lower due to the
isolated coverage and the increased fuel moisture from the
wetting rains.
62
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...Wind Advisory from 2 AM to 8 PM PDT Wednesday for Island
County-San Juan County.
Wind Advisory from 2 AM to 5 PM PDT Wednesday for Grays Harbor
County Coast-Northern Washington Coast.
PZ...Gale Watch from this evening through Wednesday evening 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-East Entrance U.S. Waters Strait Of
Juan De Fuca-Northern Inland Waters Including The San
Juan Islands.
&&
$$
NWS SEW Office Area Forecast Discussion