466
FXUS66 KSEW 222256
AFDSEW

Area Forecast Discussion
National Weather Service Seattle WA
256 PM PST Sat Feb 22 2025

.SYNOPSIS...An atmospheric river will set up over Western
Washington, maintaining a wet weekend with heavy rain, gusty
winds, and high snow levels across the region. After a brief
break early Monday, a front will bring more rain and gusty winds
through Tuesday. High pressure rebuilds over the region around the
middle of the week with mild and mostly dry conditions, though
some shower chances linger near the coast.

&&

.SHORT TERM /TONIGHT THROUGH TUESDAY/...We`re in an active period
of weather across western WA through early next week. Main weather
impacts are focused on heavy rain and potential river flooding,
strong wind (tonight and Monday night), and high seas along the
coast (Monday night).

Windiest parts this afternoon and evening will be along the coast
and North Interior where a Wind Advisory remains in effect through
7 PM PST. Gusts to 35-50 MPH expected but will taper down moving
through the evening.

In regards to flooding, another band of moderate to heavy
rainfall will track through the region tonight with several
inches falling over the Olympics and Cascades. Rivers flowing off
the mountains will see sharp rises with potential for reaching
flood stage. Snow levels will rise to over 6,000 ft meaning mostly
rain in the mountains (also creating very dangerous avalanche
conditions per NWAC). There`s another round of heavy precip
slated for Sunday afternoon/evening keeping rivers running high.
The current batch of county Flood Watches will remain in effect
given some uncertainty in total rainfall amounts and timing.

Moving forward into Monday, lower snow levels will limit further
flood concerns due to additional precipitation. However, the focus
will then shift toward another round of potential strong wind as
a 980 mb low tracks northward offshore, then inland. This is
prompting Storm/Gale Watches for the marine waters with possible
high surf (see below). For land winds, it`s worth noting that a
few ensemble members show high wind in the interior (likely based
if the low tracks NE through southern B.C.). Will need to keep a
close eye on the storm track as we close in. 33

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...A ridge brings a break
in the pattern moving into Wednesday. The air mass will remain
mild with forecast highs in the upper 50s to around 60. A weak
front splits as it tries to move inland on Thursday (rainfall
amounts are light with just a few hundredths if anything). The
ridge then rebuilds, keeping the next system offshore through the
end of the week. 33

&&

.AVIATION...Ceilings this afternoon range from MVFR to low-end VFR
through the interior of western Washington with IFR conditions along
the coast as heavier rain begins to work its way inland. Moderate to
heavy rain will move through the area this afternoon into tonight,
and along with it ceilings and visibility lower between MVFR to IFR.
MVFR to IFR conditions will likely persist through the rest of the
TAF period as waves of rain push through western Washington on
Sunday.

South to southeast winds will continue to increase this afternoon
across the interior of western Washington Strongest gusts will be
along the coast and through the northern interior (BLI) by early
evening. As winds increase, some low level wind shear may be of
concern. Wind speeds will begin to decrease late tonight but look to
pick back up again tomorrow.

KSEA...VFR conditions early this afternoon will deteriorate to MVFR
to perhaps periods of IFR ceilings and limited visibility as heavy
rain begins to move onshore. At least MVFR conditions are expected
to persist overnight and into tomorrow.

Winds will generally be south/southwesterly. Winds are expected to
increase after this afternoon, with wind speeds of around 12 to 18
kt and gusts of 25 to 30 kt possible. Wind speeds will begin to
gradually decrease after early Sunday morning before increasing
again Sunday afternoon.

62

&&

.MARINE...A series of frontal system will maintain active conditions
this weekend into Monday. Gale force winds over the coastal waters
and the East Entrance to the Strait of Juan de Fuca will ease
tonight with a break in the strong winds tonight. Winds will
increase again on Sunday afternoon into early Sunday night.
A much stronger low pressure system will move across the offshore
waters Monday night into Tuesday. Models are beginning to come more
to a consensus and have shifted the track further east, closer to
shore. This would focus the strongest winds south of Point Grenville
and near Grays Harbor. Strong gale force winds with gusts to storm
force may be possible, and a Storm Watch has been issued. Winds look
to also increase through the interior waters as well with at least
wind gusts nearing gale force, for which a Gale Watch has been
issued. These hazards will become more refined as we get closer to
Monday. Winds will decrease on Tuesday and active conditions will
cease as broad high pressure develops across the Pacific Northwest.

Combined seas are expected to increase to 14-17 ft today and then
gradually subside to 10-12 ft by Sunday morning. Waves will rapidly
build on Monday night through early Tuesday morning. Waves in the
nearshore waters look to build up to 18 to 34 ft, though waves
approaching 30 ft cannot be ruled out in the outermost coastal
waters. Waves will gradually begin to decrease Tuesday into
Wednesday but look to remain above 10 ft.

62

&&

.HYDROLOGY...The potential remains through the weekend into early
next week for river flooding, urban flooding, and possible
landslides. Snow levels will rise to above 7000 feet tonight into
Sunday, with heavy rain over the Cascades/Olympics. Rain will pick
up tonight into Sunday, and again Monday into Tuesday. Sharp rises
will occur on several rivers across the region. The flood warning
continues for the Skokomish River at Potlatch in Mason County, as
the river is expected to reach minor flood stage tonight/Sunday
morning. The flood watch will continue Sunday into Wednesday for
most of western Washington for the continued threat of river
flooding. A hydrologic outlook will remain for Jefferson, Clallam,
and Whatcom Counties for a much lower chance of river flooding.

HPR

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...Wind Advisory until 7 PM PST this evening for Admiralty Inlet
     Area-Central Coast-North Coast-San Juan County-Western
     Skagit County-Western Whatcom County.

     Flood Watch from Sunday morning through late Tuesday night for
     Bellevue and Vicinity-Central Coast-East Puget Sound
     Lowlands-Everett and Vicinity-Lower Chehalis Valley Area-
     Olympics-Seattle and Vicinity-Southwest Interior-Tacoma
     Area-West Slopes North Cascades and Passes-West Slopes
     North Central Cascades and Passes-West Slopes South Central
     Cascades and Passes-Western Skagit County.

PZ...Small Craft Advisory until 10 AM PST Monday for Grays Harbor Bar-
     West Entrance U.S. Waters Strait Of Juan De Fuca.

     Gale Watch from Monday morning through late Monday night for
     Coastal Waters From Cape Flattery To James Island 10 To 60
     Nm-Coastal Waters From Cape Flattery To James Island Out 10
     Nm-West Entrance U.S. Waters Strait Of Juan De Fuca.

     Gale Warning until 7 PM PST 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-East Entrance U.S. Waters Strait Of
     Juan De Fuca.

     Gale Watch from Monday afternoon through Tuesday morning for
     Admiralty Inlet-East Entrance U.S. Waters Strait Of Juan De
     Fuca-Northern Inland Waters Including The San Juan Islands-
     Puget Sound and Hood Canal.

     Small Craft Advisory until 7 PM PST this evening for Admiralty
     Inlet-Northern Inland Waters Including The San Juan Islands.

     Small Craft Advisory from 7 PM this evening to 10 AM PST Monday
     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.

     Storm Watch from Monday morning through late Monday night for
     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.

&&

$$