Brier Weather Station
Latitude N 47° 46' 49" Longitude W 122° 16' 48" Elevation 341 ft
555
FXUS66 KSEW 112219
AFDSEW
Area Forecast Discussion
National Weather Service Seattle WA
319 PM PDT Wed Mar 11 2026
.SYNOPSIS...
A cold front will pass over the area this afternoon, bringing
breezy winds, lowland rain, and mountain snow. Active pattern
will continue with lowland rain and heavy mountain snow through
the end of the week and into the weekend as a weak atmospheric
river develops.
&&
.SHORT TERM /TONIGHT THROUGH FRIDAY/...
A developing cold front offshore will swing across western
Washington this afternoon, bringing breezy winds, lowland rain,
and heavy mountain snow. The forecast still remains on track
for impactful weather this afternoon and evening. Key points can
be listed below for various impacts:
* WIND: As this cold front moves over the region later this
afternoon, south to southwesterly winds will increase over the
majority of the area, with wind gusts around 40 to 50 mph
expected for much of the area. A Wind Advisory is in effect
for all of the lowland areas. Areas along the coast, and
especially Whidbey Island Northward may see briefly stronger
wind gusts at times, around 55 mph as post frontal winds
funnel through the Strait. Breezy winds will peak this
evening, and start to slowly subside overnight and into
Thursday morning.
* SNOW: Heavy mountain snowfall is expected
over the next several days as a long duration event. Along
with snow occuring in the mountains, those breezy winds will
contribute to Blizzard conditions, as a Blizzard Warning is
out until Thursday morning. Snow levels will rise this
evening, giving a brief transition to rain, most likely at
Snoqualmie Pass. Snow levels will then drop down again tonight
and into Thursday below pass levels, with a couple of feet of
snow expected through Friday, especially at Stevens and
Snoqualmie.
* RAIN: Lowland rain will continue through Friday as a weak
atmospheric river continues pushing precipitation into the
area, with most of the QPF located in the mountains and along
the coast. Could see 1.5 to 3 inches of rain, especially for
areas Seattle southward, with generally 0.50 to 1 inch
elsewhere throughout the interior areas. See .HYDROLOGY
section below for more information about potential river
flooding.
.LONG TERM /FRIDAY NIGHT THROUGH WEDNESDAY/...
Ensembles showing an upper level ridge building offshore pushing
the weak atmospheric river southward. Northwesterly flow
develops on Saturday keeping showers around the area, mostly in
the Cascades along with mountain snow continuing. Guidance is
continuing to show another atmospheric river attempting to move
over the ridge into western Washington Sunday/Monday. Snow
levels rising upwards to 7000 to 8000 feet with more rain on the
way. Uncertainty remains of the ridge will push the river
upwards to BC. Will continue to monitor the forecast as it
evolves.
Mazurkiewicz
&&
.AVIATION...
A trough in the Gulf of Alaska will continue to drive a strong upper
level jet over the region. This will drive a strong frontal system
through the TAF period, with the warm sector passing through this
afternoon/evening, and a stronger cold front shortly behind Thursday
morning. Rain will continue to fall in the lowlands, with snow in
the mountains. Some of the precipitation may be heavy at times,
reducing visibilities down to IFR. The precipitation coverage will
lesson Thursday. Ceilings are favored to remain MVFR in the majority
of the interior terminals, with IFR/LIFR in the mountains/coastal
terminals. Ceilings trend Thursday towards MVFR/VFR, although the
chances of ceilings decreasing towards IFR increases Thursday
evening. Winds will continue to pick this afternoon into Thursday
morning, with winds peaking at 20-25 kt (sustained) with gusts to 30-
35 kt (a few gusts to 40 kt will be possible). There will also
continue to be instances of speed shear (due to higher winds aloft,
but the direction from aloft to the surface will continue to remain
out of the west). Winds will diminish Thursday, but a few gusts to
20 kt will remain likely at times.
KSEA...Steady rain with reduced visibilities at times will continue
through tonight - will taper to showers Thursday morning. Ceilings
are favored to remain MVFR through the TAF period (although there is
a low chance of improvement to VFR from 06Z - 15Z). Southwest winds
to increase to 20 kt gusting to 35 kt this evening into Thursday
morning, diminishing to 8-12 kt gusting to 20 kt during the day.
HPR
&&
.MARINE...
A strong weather system today will bring strong winds and high seas
to the region. Winds will continue to increase this afternoon to
Gale Force across area waters today, with Storm Force winds across
the Eastern Strait of Juan de Fuca. Seas will also quickly build
along the coast today, peaking at around 18-20 feet over the outer
coastal waters before quickly receding on Thursday to below 10 feet.
Additional systems will cross the waters later this week. A weaker
system will move over the waters on Thursday and Friday, with winds
shifting to the north Friday morning. Another system will follow on
Sunday, bringing potential for SCA winds across the coastal waters.
Latest guidance suggests seas will remain below 10 ft through the
weekend.
15
&&
.HYDROLOGY...
The heavy mountain precipitation but with lower snow level scenario
will continue to make river forecasting difficult into Sunday. QPF
values continuing to trend slightly lower for western Washington has
kept most hydrographs below flood stage for area rivers except the
Skokomish River. However, the Skokomish River continues to run lower
than the latest river forecast. A Flood Watch remains in effect for
Mason County for the potential for the Skokomish River to briefly
reach minor flood stage by early Thursday, with additional chances
for flooding early next week. While the remainder of the river
forecasts to not highlight any flooding, plenty of rivers from King
county southward will crest in action stage over the next few days.
Will be keeping an eye on the scenario developing the first part of
next week with the higher snow levels much more conducive to
flooding possibilities for the rivers.
Felton/15
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...Wind Advisory from 3 PM this afternoon to 6 AM PDT Thursday
for City of Seattle-Downtown Everett / Marysville Area-
Eastern Kitsap County-Eastern Strait of Juan de Fuca-
Eastside-Foothills and Valleys of Central King County-
Foothills and Valleys of Pierce and Southern King
Counties-Foothills and Valleys of Snohomish and Northern
King Counties-Foothills and Valleys of Thurston and Lewis
Counties-Foothills and Valleys of the North Cascades-
Foothills of the Western and Southern Olympic Peninsula-
Grays Harbor County Coast-Island County-Lake Crescent
Area Including US 101-Lower Chehalis River Valley-
Lowlands of Lewis and Southern Thurston Counties-Lowlands
of Pierce and Southern King Counties-Lowlands of Western
Skagit and Northwestern Snohomish Counties-Lowlands of
Western Whatcom County-Middle Chehalis River Valley-
Northern Hood Canal-Northern Washington Coast-Olympia and
Southern Puget Sound-Port Townsend Area-San Juan County-
Shoreline / Lynnwood / South Everett Area-Southern Hood
Canal-Western Strait of Juan de Fuca-Willapa and Black
Hills.
Winter Weather Advisory until 6 PM PDT this evening for
Cascades of Pierce and Lewis Counties-Cascades of
Snohomish and Northern King Counties-Cascades of Southern
King County-Cascades of Whatcom and Skagit Counties.
Blizzard Warning from 6 PM this evening to 5 AM PDT Thursday
for Cascades of Pierce and Lewis Counties-Cascades of
Snohomish and Northern King Counties-Cascades of Southern
King County-Cascades of Whatcom and Skagit Counties-
Olympics.
Winter Storm Warning from 5 AM Thursday to 5 AM PDT Saturday
for Cascades of Pierce and Lewis Counties-Cascades of
Snohomish and Northern King Counties-Cascades of Southern
King County-Cascades of Whatcom and Skagit Counties-
Olympics.
Flood Watch from 5 PM PDT this afternoon through Thursday
afternoon for Foothills of the Western and Southern
Olympic Peninsula-Middle Chehalis River Valley-Olympia
and Southern Puget Sound-Olympics-Southern Hood Canal-
Willapa and Black Hills.
PZ...Small Craft Advisory until 2 AM PDT Thursday for Grays Harbor
Bar.
Gale Warning until 2 AM PDT Thursday for Admiralty Inlet-
Central U.S. Waters Strait Of Juan De Fuca-Northern
Inland Waters Including The San Juan Islands-Puget Sound
and Hood Canal-West Entrance U.S. Waters Strait Of Juan
De Fuca.
Storm Warning until 2 AM PDT Thursday for East Entrance U.S.
Waters Strait Of Juan De Fuca.
Gale Warning until 2 AM PDT Thursday 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