Brier Weather Station
Latitude N 47° 46' 49" Longitude W 122° 16' 48" Elevation 341 ft
758
FXUS66 KSEW 092120
AFDSEW
Area Forecast Discussion
National Weather Service Seattle WA
220 PM PDT Mon Mar 9 2026
.SYNOPSIS...
A very active pattern is taking shape and will persist
throughout the week for western Washington. Periods of heavy
mountain snow, lowland rain, gusty winds and possible river
flooding are in the forecast.
&&
.SHORT TERM /TONIGHT THROUGH WEDNESDAY NIGHT/...
Impressively zonal flow over the greater northeastern Pacific
will keep the door open for storms to move through western
Washington throughout the week. For the rest of today, expect
scattered showers throughout the lowlands, with continued
periods of snow in the Olympics and Cascades. Tonight into
Tuesday morning will likely be the coldest of the week, with
snow levels dropping practically to the surface overnight.
Anywhere that experiences shower activity during the peak of
this cold air is susceptible for some snow, but likely not
accumulating for non-mountainous regions.
The system arriving Wednesday will be rather strong, and feature
strong winds in the afternoon and into late Wednesday night. As
such, Blizzard Warnings have been posted for the Cascades and
Olympics for winds frequently gusting to around 40 to 45 mph as
well as visibility reductions down to a quarter of a mile. The
Cascade passes will be primarily impacted by these winds, but
the Olympics and routes to Hurricane Ridge will also be impacted
by blowing snow and strong winds. For travel conditions across
the passes, please refer to WSDOT for the latest.
&&
.LONG TERM /THURSDAY THROUGH MONDAY/...
A number of winter weather headlines will persist into the later
half of the week as additional rounds of heavy snow are expected
in the mountains. Wednesday through Friday morning storm total
snow amounts suggest 2-4 feet across Stevens and Snoqualmie
pass, but higher amounts at higher elevations are possible and
could reach up to 5 feet of new snow. This is welcome news for
the state of the snowpack and snow water equivalent values that
have been abysmally low thus far this winter. While not likely
to fully rebound conditions to a normal value, it is still of
benefit.
Atmospheric river activity will also lend itself to higher QPF
amounts in lowland locations, generally areas from Seattle
southward to the Chehalis Valley are forecast to receive the
most QPF at this time. These locations are also included in
Excessive Rainfall Outlooks from the Weather Prediction Center
in the midweek time frame as well. Winter storm watches persist
into the later half of the week and may be upgraded depending
on the forecast over the next several days.
Rain and periods of mountain snow look to continue into early
next week.
21
&&
.AVIATION...
Westerly, zonal, flow over western WA tonight and
Tuesday both at the surface and aloft. Disturbances aloft will
maintain scattered showers with a slight chance of
thunderstorms, primarily along the coast. Ceilings are mostly
VFR with possible MVFR conditions in passing showers. 33
KSEA...Showers in the vicinity through around 06z tonight. S/SW
winds with gusts to 20-25kt through 03-06z. Brief MVFR cigs
possible early Tuesday morning. Showers increase by 21z Tuesday
afternoon. 33
&&
.MARINE...
Onshore flow will ease tonight. Seas will remain
elevated through Wednesday. A strong Pacific frontal system
will impact the region on Wednesday with potential for gales
over the waters. A weaker system will stall over the region
Thursday and Friday. The flow will turn northerly on Saturday,
then offshore on Sunday as a warm front moves into southern B.C.
33
&&
.HYDROLOGY...
Moderate to heavy rainfall over the Olympics will
force rises on the Skokomish River in Mason County with flooding
possible. The river will remain high through the end of the
week. Flooding is also possible on the Chehalis basin rivers
including the Chehalis, Newaukum River and Skookumchuck River
near Bucoda. Crests on these river will occur late in the week.
Several other rivers are forecast to reach Action Stage this
week but not flooding. An AR next week is primarily focused
north into B.C. but will need watching for any southern
tracks into WA.
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...Winter Storm Warning until 5 AM PDT Tuesday for Cascades of
Snohomish and Northern King Counties-Cascades of Whatcom
and Skagit Counties.
Winter Weather Advisory from 5 AM to 5 PM PDT Tuesday for
Cascades of Snohomish and Northern King Counties-Cascades
of Whatcom and Skagit Counties.
Blizzard Warning from 5 PM Tuesday to 11 PM PDT Wednesday 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 Watch from Wednesday evening through Friday
morning 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 Weather Advisory until 5 PM PDT Tuesday for Cascades of
Pierce and Lewis Counties-Cascades of Southern King
County.
Winter Weather Advisory until 11 AM PDT Tuesday for Foothills
and Valleys of Snohomish and Northern King Counties-Lake
Crescent Area Including US 101-Western Strait of Juan de
Fuca.
Flood Watch from Wednesday 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 5 PM PDT Tuesday for Grays Harbor
Bar.
Small Craft Advisory until 11 PM PDT this evening for Central
U.S. Waters Strait Of Juan De Fuca-East Entrance U.S.
Waters Strait Of Juan De Fuca.
Small Craft Advisory until 2 PM PDT Wednesday 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 Watch from Wednesday afternoon through Wednesday 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