754
FXUS66 KSEW 110305
AFDSEW
Area Forecast Discussion
National Weather Service Seattle WA
805 PM PDT Tue Mar 10 2026
.SYNOPSIS...
Active weather continues, with a stout front on the way tomorrow
evening, lasting into Thursday morning. Additional systems are
poised to move through the region through the weekend, with
heavy mountain snow and lowland rain expected through this time
period. A threat of river flooding remains in the forecast for
areas south of Olympia.
&&
.SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/...Western Clallam
County area including 101 and Lake Crescent was added to the
Wind Advisory, joining the remaining lowland areas poised for
strong winds Wednesday night. Otherwise, no other adjustments to
current headlines. 33
Previous discussion...A wave of showers is beginning to make
its way into Puget Sound this afternoon. Given the snow levels
and present temperatures, this should fall as rain for lowland
locations, with some light snow in the Cascades by the time it
gets there.
A strong cold front will approach the area tomorrow, driving up
the winds by the late morning, peaking late Wednesday into early
Thursday morning. Blizzard warnings in the Cascades and Olympics
remain intact, but the wind forecast for lowland locations also
increased. Winds in the Cascades are still forecast to gust
between 35 and 45 mph, but with the 850 mb winds also indicating
50-55 mph winds, high elevation locations could gust higher than
that. Additionally, wind advisories have been posted to begin
Wednesday afternoon and last through Thursday morning. Winds
will begin as strong southwesterly winds, and for areas north of
Everett, expect a transition to strong northwesterly winds in
the late evening as a strong push occurs through the Strait of
Juan de Fuca. Areas south of Everett will remain southwesterly.
At the onset of this event, snow levels are forecast to rise to
around 5000-6000ft before coming back down late Wednesday night
into Thursday morning. During the period where the snow levels
are higher, expect a period of rain in the Cascade passes on top
of whatever snow has fallen. Temperatures will cool overnight
for concerns of re- freezing over the roadways. Travel
conditions could be very difficult with all of these factors
combined.
QPF amounts in lowland locations will be between 1.5 to 3 inches
through Friday for areas from Seattle south, with around a half
to one inch in areas north of the metro. The higher amounts are
forecast for the Chehalis Valley, where some area rivers are
forecast to rise into minor flood stages.
After these hazards begin to taper off early Thursday morning,
mountain showers will continue into Friday.
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...Heavy snow is expected to
continue on Friday into the weekend, and Winter Storm Watches
remain posted for the late week/weekend period. Snow levels
remain around 2500 feet or less. By Saturday, area snow levels
drop below 1000 feet, so depending on moisture availability,
there is also a chance for some of the higher hills amidst the
lowland locations to receive a dusting of snow come Saturday
morning.
Forecast guidance is still holding onto another potential
atmospheric river coming overtop a building ridge to the south
of the Pacific Northwest on Sunday into Monday. Right now it`s
too early to tell how much rain will fall from this system, but
confidence is elevated in wet conditions lingering into early
next week before the influence of the ridge may become more
apparent.
21
&&
.AVIATION...West-northwesterly flow aloft with generally
southerly winds at the surface. Breezy winds remain at most
terminals, generally ranging 10- 15 kts with gusts up to 25 kts
this evening and tonight. Speeds may ease slightly overnight,
ranging 8-12 kts before ramping back up again significantly by
Wednesday afternoon.
A mix of VFR to MVFR conditions out there, depending on location.
Much of the Olympic Peninsula remains VFR at the time of this
writing while points east are largely MVFR...where the majority of
precip activity is occurring. Showers will persist overnight, giving
rise to widespread MVFR cigs by early Wednesday morning...while
locations prone to lower cigs could find themselves in IFR
conditions. Cigs expected to degrade even further as main front
moves through the area Wednesday. While conditions are expected to
remain in low-end MVFR, terminals that fell into IFR during the
overnight period are likely to remain there during FROPA.
KSEA...MVFR conditions in place with nearby showers. Activity is
expected to persist but does appear to be weakening. While this may
allow for a brief recovery period, opting to side with MVFR
conditions persisting in the near term and will re-evaluate for the
06Z issuance. While gusts seem to have eased, breezy winds 10-15 kts
persist this evening with the expectation that they will ease a
little bit overnight, as discussed above. Stratiform rain still
expected to move in early Wednesday morning, degrading cigs somewhat
but still maintaining MVFR conditions. S/SW winds will increase
midday Wednesday with gusts briefly reaching 30-35 kt at the
terminal Wed afternoon.
18
&&
.MARINE...Small Craft Advisories remain in effect for the Puget
Sound, Admiralty Inlet, and Salish Sea this afternoon and
evening as a frontal system progresses inland. SCAs for the
coastal waters remain in effect as well for westerly winds and
elevated seas. A much stronger storm system will move over the
region on Wednesday, with the potential to bring Gale Force
winds to all area waters. Gale Watches for the coastal waters
and through the Strait of Juan de Fuca have been upgraded to
Gale Warnings, and Gale Watches have been issued for the Puget
Sound, Admiralty Inlet, and Salish Sea for potential for gale
strength gusts later on Wednesday. A brief window of Storm Force
gusts are also possible as hi-res guidance is showing a
moderate (30-50%) chance of them occuring over the Central and
Eastern Strait on Wednesday evening.
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.
Seas remain around 8-13 ft this afternoon before easing to around 7
to 9 feet overnight into Wednesday morning. Seas will briefly rise
as high as 15-18 feet across the coastal waters Wednesday afternoon
into early Thursday. This rise may create the need for another SCA
for the Grays Harbor bar during this time frame. Seas then ease to
around 6 to 9 feet by Thursday afternoon and remain below 10 feet
thereafter.
15/18
&&
.HYDROLOGY...Moderate to heavy precipitation over the Olympics
will cause the Skokomish River in Mason County to rise with
flooding possible on Thursday. The river will remain high
through the end of the week with additional crests forecast to
reach minor flood stage.
Flooding is also possible on the Chehalis river from Grand
Mound to Grays Harbor, Newaukum River and Skookumchuck River
near Bucoda beginning Thursday-Saturday. Total precipitation has
decreased with lower crests but still close to Minor Flood
stage. Will continue to monitor.
Another atmospheric river will move over the area early next
week. With the already high running rivers ahead of the event
this will be closely watched for another round of possible river
flooding.
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...Wind Advisory from 3 PM Wednesday to 6 AM PDT Thursday for
City of Seattle-Downtown Everett / Marysville Area-
Eastern Kitsap County-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-Island County-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-Olympia and Southern Puget
Sound-San Juan County-Shoreline / Lynnwood / South
Everett Area-Southern Hood Canal-Willapa and Black Hills.
Winter Weather Advisory until 6 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.
Blizzard Warning from 6 PM Wednesday 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 Watch from late Wednesday night through late
Friday night 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 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.
Wind Advisory from 6 PM Wednesday to 6 AM PDT Thursday for
Eastern Strait of Juan de Fuca-Grays Harbor County Coast-
Lake Crescent Area Including US 101-Northern Washington
Coast-Port Townsend Area-Western Strait of Juan de Fuca.
PZ...Gale Warning from 2 PM Wednesday to 2 AM PDT Thursday 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 until 8 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.
Gale Watch from Wednesday afternoon through late Wednesday
night for Admiralty Inlet-Northern Inland Waters
Including The San Juan Islands-Puget Sound and Hood Canal.
Small Craft Advisory until 11 PM PDT this evening for Puget
Sound and Hood Canal.
Small Craft Advisory until 11 AM 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 Warning from 11 AM Wednesday 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