Brier Weather Station
Latitude N 47° 46' 49" Longitude W 122° 16' 48" Elevation 341 ft
471
FXUS66 KSEW 111053
AFDSEW
Area Forecast Discussion
National Weather Service Seattle WA
353 AM PDT Wed Mar 11 2026
.SYNOPSIS...
Fast moving strong cold front moving through Western Washington
late this afternoon and this evening bringing, rain and windy
conditions to the area. Wet pattern continuing through Friday
with a weak atmospheric river taking aim at Western Washington.
The river sags south Friday night as an upper level ridge builds
offshore. Systems moving over the top of the ridge will likely
bring more rain to Western Washington early next week. Snow
levels rising significantly beginning Sunday.
&&
.SHORT TERM /TODAY THROUGH FRIDAY/...
A little lull in the action early this morning but the inherited
forecast is on track. Satellite imagery shows fast moving system
offshore. Rain out ahead of the system starting to fill in over
the area. Westerly flow aloft causing a rain shadow over the
Central Puget Sound. Temperatures were in the upper 30s to mid
40s at 3 am/10z. A touch warmer than the last few mornings.
Everything still on track for some impactful weather across the
area beginning this afternoon. Developing cold front offshore
just east of 140W at 10z. The 160 knot jet accompanying the
front will drive the system quickly across the eastern Pacific
into Western Washington by late afternoon. Rain will continue to
fill in over the area this morning with the rain shadow giving
way by mid morning. Rain continuing through the afternoon hours.
Front reaching the coast mid afternoon moving inland quickly.
In addition to the rain winds picking up this afternoon
especially along the coast. Have made a small change and moved
the start time of the wind advisory along the coast up a couple
of hours to 3 pm. By late afternoon westerly winds gusting 45-55
mph along the coast. Gusty southwesterly winds picking up over
the interior as well with gusts near 40 to 45 mph by late
afternoon. Snow levels below the passes initially will rising to
4000 to 4500 feet this afternoon. This rise in the snow levels
will be brief with snow levels dropping again behind the front.
Highs near 50.
Front slamming into the Cascades early this evening with 925 mb
and 850 mb winds in the 40-55 knot range. Strongest winds in the
Central Cascades. Snow levels dropping quickly back down below
the passes. Strong orographics will produce significant snow.
This combined with the winds will create blizzard conditions in
the passes especially late tonight. The blizzard warning for
tonight remains in effect until 5 am Thursday.
In the lowlands strong post frontal onshore flow. KOLM-KBLI
gradient peaking near plus 6 mb just ahead and with the front.
Gradients in the Strait of Juan de Fuca will go from - 1 mb in
the middle of the afternoon to plus 5 mb by 03z/8pm. Wind
advisory remains in effect for all of the lowlands. Expect the
strongest winds, gusts 50-55 mph along the coast and the north
portion of Whidbey Island. The low level convergence will create
an area of lighter winds probably near Everett. For the
remainder of the area winds gusting 40-45 mph easing after
midnight. Post frontal showers overnight. Can`t rule out an
isolated thunderstorm as well. Convergence zone will form
over Snohomsih county but with the strong winds aloft the zone
will get pushed into the Cascades quickly. This will enhance the
new snow totals near Stevens Pass. Lows near 40.
Small break in the action Thursday morning as winds continue to
ease and shower activity decreases. Jet aimed at Western
Washington remaining healthy, 120 knots or so, will push a weak
atmospheric river into Western Washington by the end of the
afternoon. With the area slightly on the cool side of the jet,
snow levels remaining below the passes. Highs back down into the
mid 40s.
Weak atmospheric river, IVT values around 500 kg/m/s, remaining
over Western Washington Thursday night and Friday. Rain in the
lowlands and snow in the mountains. Snow levels remaining below
the passes making for a tough go across the mountains. Have
converted the Winter Storm Watch for early Thursday morning
through early Saturday morning into a Winter Storm Warning. One
to as much as three feet of new snow ( Paradise on Mt Rainier )
possible during the warning time frame. Temperatures remaining
below normal, lows in the mid and upper 30s and highs in the
mid 40s. Felton
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
Extended models in good agreement with an upper level ridge
beginning to build offshore pinching off the atmospheric river
and pushing it south out of the area Friday night. Cool
northwesterly flow aloft keeping some showers around Saturday
with most of the activity in the Cascades. Models still showing
uncertainty Sunday into the first part of next week. Upper level
ridge remaining offshore with another atmospheric river trying
to move over the top of the ridge into Western Washington. There
is good agreement that the air mass will warm up with snow
levels rising significantly, up to as high as 8000 feet. The
question is will the ridge be able to push the river north into
British Columbia. Ensembles are trending towards the ridge not
being strong enough to deflect the river so for this package
will have rain or rain likely wording for Sunday night through
Tuesday. Highs will warm up with low 60s possible by Tuesday.
Felton
&&
.AVIATION...
Widespread MVFR conditions early this morning, with a few locations
of IFR, expected to continue today as a strong weather system pushes
across the terminals this afternoon. Rain showers continue to move
across the terminals early this morning and expecting rain to become
steadier after 12z. IFR vis possible (10-20% chance) this afternoon
as the heavier rain moves through the terminals between 14z-23z.
S/SW winds will increase this afternoon, peaking this evening into
tonight with gusts 30-40 kt expected. Winds will ease slightly early
Thursday morning but will still remain breezy.
KSEA...MVFR cigs at the terminal expected to continue today, with
stratiform rain reaching the terminal by 14z. There is a small
chance(15-20%) of IFR vis between 14z-20z as the heavier rain pushes
through. Gusty S/SW winds this afternoon through tonight. Winds will
peak this evening with gusts 30-35 kt expected after 1z. Latest
guidance suggests winds will begin to gradually ease after 7z, but
still remaining breezy with gusts to 20-25 kt into Thursday morning.
29
&&
.MARINE...
A strong weather system today will bring multiple marine hazards.
For the coastal waters and West Strait, hazards will include a
combination of elevated waves and gale force winds. Early this
morning seas are hovering around 8-10 ft and will build Wednesday
afternoon to 14-19 ft. There is increasing confidence (greater than
80%) of seeing gale force winds over Puget Sound, Admiralty Inlet
and the Northern Interior waters. Therefore, the Gale Watches have
been upgraded to Gale Warnings. Latest high-res guidance suggests
there is a moderate-high chance (70-85%) for the coastal waters of
briefly seeing Storm Force gusts Wednesday afternoon. There is also
a moderate chance (50-70%) of Storm Force gusts for the Central and
East Strait of Juan de Fuca Wednesday evening. Additional systems
expected throughout the 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.
Seas and winds will begin to ease Thursday morning, with seas
decreasing below 10 ft Thursday night. Latest guidance suggests seas
will remain below 10 ft through the weekend.
29
&&
.HYDROLOGY...
The heavy mountain precipitation but with lower snow level
scenario will continue to make river forecasting difficult into
Sunday. QPF values a little lower on latest run which has
dropped the hydrographs back down below flood stage for all of
the rivers except the Skokomish. Even the Skokomish is running
lower than the current forecast. Watch remaining in effect for
Mason county because of the Skokomish with the river possibly
getting to flood stage Thursday or Friday. Also a chance of the
river getting to flood stage with the warm events next week.
While the remainder of the river forecasts to not show any
flooding plenty of rivers from King county southward cresting
in action stage 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
&&
.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 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 from 11 AM this morning to 2 AM PDT
Thursday for Grays Harbor Bar.
Gale Warning from 2 PM this afternoon to 2 AM PDT Thursday for
Admiralty Inlet-Central U.S. Waters Strait Of Juan De
Fuca-East Entrance 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.
Small Craft Advisory until 11 AM PDT this morning 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.
Gale Warning from 11 AM this morning to 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