Brier Weather Station
Latitude N 47° 46' 49" Longitude W 122° 16' 48" Elevation 341 ft
390
FXUS66 KSEW 251028
AFDSEW
Area Forecast Discussion
National Weather Service Seattle WA
328 AM PDT Fri Sep 25 2026
.SYNOPSIS...
A surface low will move southwest to northeast today bringing
increasing winds to the area. High pressure will build in
tonight with winds easing quickly. Upper level trough will move
through today as well bringing showers and a chance of
thunderstorms. The trough will move east tonight with drying
northwesterly flow aloft. Upper level trough digging offshore
with split flow aloft off the coast for a dry weekend. Flow
aloft becoming zonal Monday with a chance of rain in the
forecast at times next week.
&&
.SHORT TERM /TODAY THROUGH SUNDAY/...
Satellite imagery does not look like the last week of September.
Cold front east of the metro area early this morning with a bent
back occlusion off the coast. Steady rain ended a little after
midnight over the interior. Doppler radar has shower activity
over the northern portion of the area. Temperatures at 3 am/10Z
were in the lower to mid 50s.
Lots of changes to the forecast this morning. The big question
is where is the surface low off the coast associated with the
bent back occlusion going to track. Previous model runs had the
low moving inland south tracking through the Southwest Interior
this morning. There are model solutions tonight that are
sticking with this scenario. Surface observations along the
coast show the strongest surface pressure falls not near the
mouth of the Columbia River but instead between Hoquiam and buoy
41. This brings the low inland on a more northerly track with
the low center taking aim at the Central Puget Sound later this
morning. Strong surface pressure rises behind the low plus an
unstable air mass possibly mixing 925 mb winds in the 30 to 40
knot range down to the surface will create windy conditions
south of the low center. Have issued wind advisories beginning
later this morning and continuing through the afternoon hours
from Tacoma southward including the coast. In general expect
west to southwest winds gusting 35 to 45 mph with a little
stronger gusts along the coast. With plenty of foliage still on
the trees, winds this strong could bring down some branches and
cause power outages. This isn`t the only wind scenario for the
area today. As the low continues to move northeast this
afternoon surface gradients will rapidly increase through the
Strait of Juan de Fuca. Westerly wind surge coming down the
Strait this afternoon will be strong enough to produce wind
advisory strength wind gusts along the shores of the Strait of
Juan de Fuca into Whidbey Island, especially the northern end.
A wind advisory has been issued for these locations as well.
Unstable air mass moving over the area this morning with an
upper level trough over the area. Showers with a slight chance
of thunderstorms for most of the day. There will be a quick very
strong convergence zone somewhere between Seattle and Everett
this afternoon. Thunderstorm chances are higher in the
convergence zone. High temperatures in the upper 50s to mid 60s.
Wind advisory strength westerlies continuing into the early evening
hours through the Strait into Whidbey Island. For the remainder
of the area weather calming down with surface high pressure
building into the area and the upper level trough moving off to
the east. Winds through the Strait will ease before midnight.
Clearing skies will produce the coldest morning since early June
with lows in the 40s.
Saturday and Sunday looking dry at this point. Upper level
trough offshore digging south with split flow aloft off the
coast. Light surface gradients bring up the possibility of
morning fog especially Sunday. Even with sunshine, highs will
be below normal, in the lower to mid 60s. Sunday morning will be
another cool one with the colder locations getting into the
upper 30s. Felton
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
Upper level trough moving inland Monday with the flow aloft
consolidating off the coast. Models in pretty good agreement
with the next system arriving Monday night or Tuesday bringing a
chance of rain back to the forecast. Models solutions start to
lose their consistency Wednesday and Thursday. Some of the
solutions build a weak upper level ridge over the area while
other solutions bring a weak system through Wednesday night or
Thursday. Will have chance or slight chance pops both days until
model solutions consolidate. Highs remaining in the lower to mid
60s with lows in the mid 40s to lower 50s. Felton
&&
.AVIATION...
A surface low pressure system will continue to northeast across the
terminals today. The center of the low will track from southwest
Washington into Puget Sound through the day, bringing an occluding
front through. The first bands of rain are moving through the
Cascades and the north interior, with additional wrap around
moisture on the west side of the low offshore this morning along the
coast. This will move inland into the afternoon, with activity
becoming more showery in nature. There remains a 20-25% chance of
thunder for all the terminals today. Ceilings will gradually lower
this morning with a mix of MVFR ceilings for Puget Sound, and
outside areas seeing IFR to LIFR ceilings. Some mist will likely
accompany the low ceilings. Improvement will likely prolong into
late this afternoon with additional rain moving through - with
models hinting 21-00Z for VFR improvement in the central/south
interior only. Models are indicating widespread LIFR conditions
Saturday morning, especially in the interior.
Winds will become increasingly gusty this morning, starting out of
the southwest and becoming more westerly on the backside of the low.
Sustained winds of 15-20 kt with gusts up to 30 to 35 kt are
expected, particularly in the south interior, Pacific Coast, and
Whidbey Island/Salish Sea Coast. Isolated wind gusts over 40 kt are
possible in the Strait of Juan de Fuca. The winds will decrease
Friday night into Saturday to 5 kt or less.
KSEA...Ceilings will decrease to MVFR this morning with areas of
mist behind the first round of rain. The next round of rain will
move through late this morning and afternoon and will be more
showery in nature. There remains a 20% chance of thunder through the
day. VFR improvement will take place later in the day (00Z). There
are increasing chances for LIFR conditions Saturday morning from 12Z-
18Z. Winds will pick up after 18Z to 10-15 kt with gusts to 25 kt
out of the southwest through 06Z, decreasing to 5 kt out of the
south Saturday morning.
HPR
&&
.MARINE...
A surface low pressure and frontal system is tracking through the
coastal waters this morning, with the center of the low just off of
Astoria OR. Radar has an area of thunderstorms around the center of
the low moving to the northeast. Additional thunderstorms will be
possible today in the coastal and interior waters as the system
tracks northeastward.
With pressure drop observations at buoy 41 this morning (2 mb an
hour) and high-resolution models indicating stronger winds, the
gale warning was expanded to include all of the coastal waters for
today. The gale warning continues for the Strait of Juan de Fuca,
and the small craft advisory in the interior waters now includes the
Admiralty Inlet. The strongest winds this morning will be in the
southern coastal waters where gusts up to 40 kt are expected as
winds increase out of the northwest behind the low. A strong push in
the Strait of Juan de Fuca will also bring west wind gusts up to 40
kt later this afternoon and evening. The remaining Puget Sound/North
Interior waters will see winds increase late this morning and
afternoon, though confidence remains for only seeing small craft
impacts in these waters.
Winds will decrease tonight into the weekend, with high pressure
building offshore. A weak front will dissipate off the coast Sunday,
with a stronger system moving through the waters midweek next week
with another chance of hazardous winds and seas.
Seas will increase today to 9-12 ft with a couple instances of 13-15
ft with the highest winds. The seas will drop to 4-6 ft this weekend
into early next week, but increase back to near 10 ft with the
midweek system.
HPR
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...Wind Advisory from 10 AM this morning to 5 PM PDT this
afternoon for Foothills and Valleys of Pierce and
Southern King Counties-Foothills and Valleys of Thurston
and Lewis Counties-Lowlands of Lewis and Southern
Thurston Counties-Lowlands of Pierce and Southern King
Counties-Middle Chehalis River Valley-Olympia and
Southern Puget Sound-Southern Hood Canal-Willapa and
Black Hills.
Wind Advisory from 11 AM this morning to 8 PM PDT this evening
for Eastern Strait of Juan de Fuca-Island County-Northern
Washington Coast-Port Townsend Area-Western Strait of
Juan de Fuca.
Wind Advisory from 6 AM this morning to 5 PM PDT this
afternoon for Grays Harbor County Coast.
PZ...Gale Warning from 8 AM this morning to 5 AM PDT Saturday for
Central U.S. Waters Strait Of Juan De Fuca-East Entrance
U.S. Waters Strait Of Juan De Fuca-West Entrance U.S.
Waters Strait Of Juan De Fuca.
Small Craft Advisory from 11 AM this morning to 5 AM PDT
Saturday for Northern Inland Waters Including The San
Juan Islands.
Small Craft Advisory from 11 AM this morning to 11 PM PDT this
evening for Admiralty Inlet-Puget Sound and Hood Canal.
Gale Warning until 8 PM PDT this 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.
&&
$$
NWS SEW Office Area Forecast Discussion