Brier Weather Station
Latitude N 47° 46' 49" Longitude W 122° 16' 48" Elevation 341 ft
183
FXUS66 KSEW 021644
AFDSEW
Area Forecast Discussion
National Weather Service Seattle WA
944 AM PDT Wed Sep 2 2026
.SYNOPSIS...
Upper level low moving out of the Gulf of Alaska moving down
British Columbia coast to the Washington coastal waters
Thursday. Strong for early September cold front associated
with the low moving through late this afternoon and early this
evening bringing rain and gusty winds. The upper level low will
remain in the vicinity through the weekend for cool and
unsettled weather. Possible drying trend Monday and Tuesday as
the low moves out of the area.
&&
.SHORT TERM /TODAY THROUGH FRIDAY/...
Satellite imagery shows upper level low just southwest of Haida
Gwaii with the associated cold front off the coast near 128W.
Rain started on the North Coast in the last hour. Slightly
unstable air mass ahead of the front with doppler radar
indicating some light showers over the foothills and Cascades.
Temperatures at 3 am/10Z were in the mid 50s to lower 60s.
Everything still looks on track this morning. Upper level low
will continue to drop south today. Cold front off the coast
becoming slightly negatively tilted. This will slow down the
eastward progress of the front. Rain spreading inland west of
Puget Sound this morning and over the remainder of the area
this afternoon. Slight chance of thunderstorms well ahead of the
front this morning with the unstable air mass. South to
southeast winds increasing along the coast and over the
Northwest Interior and Admiralty Inlet later this morning. Windy
conditions, 20 to 35 mph, continuing into the afternoon hours.
Front reaching the coast late this afternoon. The wind
advisories for the coastline, Northwest Interior and Admiralty
Inlet remain in effect. Highs in the lower to mid 60s.
Front moving through the interior early this evening with steady
rain changing to showers. Breezy conditions just ahead and with
the front. Winds easing post frontal along the coast early
evening and over the interior before midnight. Lows in the mid
40s to mid 50s.
Upper level low off the coast Thursday will slowly drift inland
Friday over Oregon. Relatively cool and unstable air mass over
the area keeping showers in the forecast with a slight chance of
thunderstorms in the afternoons with a little daytime heating.
Highs remaining in the 60s. Lows Thursday night in the mid 40s
to lower 50s. The last time Seattle had a low in the 40s was
June 8th ( 49 degrees ). Felton
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
Models in general agreement with the upper level low remaining
in the vicinity through the weekend. This is not a scenario the
models are going to handle very well as far as the exact
placement of the low. At this point will have to keep at least a
chance of showers in the forecast. Temperatures slowly warming
with highs in the mid 60s to lower 70s. Lows in the upper 40s to
mid 50s.
Model solutions in good agreement given the situation with the
low kicking out to the east Monday and a weak upper level trough
moving over the area Tuesday. This scenario would confine the
shower chances to the Cascades both days. Highs remaining below
normal, in the mid 60s to lower 70s. Lows in the lower to mid
50s. Felton
&&
.AVIATION...South to southwest flow aloft will continue into
Thursday as an upper low digs southwards along the coast. Widespread
mid and high clouds this morning ahead of a frontal system that will
move onshore today. The front moves across Western Washington into
this afternoon, with widespread rainfall along the coast this
morning sliding into Puget Sound this afternoon. MVFR cigs for the
majority of today along the coast, with lowering VFR cigs for the
interior sites, briefly becoming MVFR with the frontal passage at
some locations. Post-frontal showers are then expected along the
Olympic Peninsula tonight. Cigs lowering to low-end VFR and MVFR
Thursday morning. South winds increasing this morning, peaking
between 16-21z for the coast, and 19-01z for interior sites. Gusts
will be strongest along the coast and north of PAE, the exception
being CLM. Winds will slowly ease tonight.
KSEA...VFR cigs are expected to continue for the majority of the TAF
period with widespread mid and high clouds. Cigs may briefly lower
to MVFR around 22-02z during the timing of the frontal passage.
Probabilities peak at 30% for MVFR cigs during this period. Rain is
expected to begin around 20-21z and continue through 00z. Increasing
south winds this morning, peaking between 20-01z, with peak gusts of
25 to 30 kts. Winds slowly ease tonight. JD
&&
.MARINE...A low pressure system will continue its way across the
region today as its cold front moves through W WA today while the
low center moves down through the coastal waters on Thursday. Gale
force wind gusts are expected across most of the coastal waters, and
through the northern Salish Sea from Admiralty Inlet up through the
East Entrance and into the Northern Inland Waters. Wind gusts
through the Puget Sound and Hood Canal will increase this morning,
reaching Small Craft Advisory criteria by afternoon and will
continue into possibly the early evening hours. Portions of the
central Strait of Juan de Fuca south and east of Victoria may also
see Small Craft to gale force gusts, but the majority of the zone
should stay sheltered from the strongest winds. The strongest winds
area-wide should start to decrease following the frontal passage
tonight. While winds will stay elevated over some of the interior
waters, at this time it does not look like additional headlines will
be needed. Broad low pressure will remain over region through the
end of the week into this weekend though winds look to remain light.
Chances for isolated thunderstorms will pose a threat to the area
waters today and Thursday, through probabilities remain minimal (10-
20% chc).
Seas 7-10 ft this morning increasing to 10-13 ft by noon. These
heights will not linger, as seas return to 7-9 ft late this
afternoon/early this evening. Seas briefly increase then towards 8
to 11 feet tonight into Thursday morning. Seas ease to around 4-6 ft
by Thursday night and remain like so through the weekend.
JD/18
&&
.FIRE WEATHER...
Fire weather concerns remain low through the next week. A
strong for the first week of September weather system will
bring significant rainfall to the coast and Olympics through
Thursday afternoon. Rainfall amounts in the Olympics in the 1.5
to as high as 3 inch range with 1 to 1.5 inches along the
coast. Elsewhere amounts will be lower but most areas should see
a wetting rain. Rainfall may pose a minor threat to highly
sensitive and brand new burn scars. Chances for showers will
continue through the weekend with a slight chance of
thunderstorms Thursday and Friday afternoon. The risk of new
fire starts is low due to the isolated coverage and the
increased fuel moisture from the wetting rains. Even with a
drier pattern next week temperatures will remain a little below
normal keeping fire weather concerns in check. Felton
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...Wind Advisory until 8 PM PDT this evening for Island County-
Lowlands of Western Skagit and Northwestern Snohomish
Counties-Lowlands of Western Whatcom County-Port Townsend
Area-San Juan County.
Wind Advisory until 5 PM PDT this afternoon for Grays Harbor
County Coast-Lowlands of Lewis and Southern Thurston
Counties-Northern Washington Coast.
PZ...Small Craft Advisory until 5 PM PDT this afternoon for Grays
Harbor Bar.
Gale Warning until 11 PM PDT this evening for Admiralty Inlet-
East Entrance U.S. Waters Strait Of Juan De Fuca-Northern
Inland Waters Including The San Juan Islands.
Small Craft Advisory until 11 PM PDT this evening for Puget
Sound and Hood Canal.
Gale Warning until 5 PM PDT this afternoon 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.
Small Craft Advisory from 5 PM this afternoon to 11 AM PDT
Thursday 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