904
FXUS66 KSEW 120937
AFDSEW
Area Forecast Discussion
National Weather Service Seattle WA
137 AM PST Mon Jan 12 2026
.SYNOPSIS...
A weak atmospheric river will produce periods of moderate to
locally heavy rain into tonight. High pressure aloft begins to
rebuild into the region on Tuesday and will persist through the
remainder of the week for an extended stretch of dry conditions.
&&
.SHORT TERM /TODAY THROUGH WEDNESDAY/...
A stalled frontal boundary continued to produce moderate to
locally heavy rainfall across the northwest half of the CWA
overnight along with gusty winds coast and North Interior areas.
As atmospheric rivers go, this one has been thankfully on the
weaker side and has thus limited the threat of flooding to the
Skokomish River so far. More on this can be found in the
hydrology discussion. Periods of rain will continue to be
largely focused on the northwest half of Western Washington
today before the frontal boundary responsible for it finally
lifts northward tonight in response to a broad upper ridge
expanding northward into the region. This will dry most of the
area out by Tuesday morning. The region will remain in a very
mild air mass on Tuesday and, despite persistent cloud cover
much of the day, high temperatures in the mid (and perhaps
upper) 50s will tease a few records around the area. An upper
level ridge remains in control into Wednesday and, as alluded to
a couple nights ago, one last approaching front will mostly
likely get washed out before it ever manages to make it onshore.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...A high amplitude
upper ridge axis takes up residence just offshore Thursday into
at least the early portion of the weekend. The only real
forecast challenge during the period will be high temperatures
and day-to-day fog coverage in the interior lowlands. Low level
offshore flow reaches a zenith in the Friday to Saturday period
as a 1040-ish millibar surface high settles over the interior
of British Columbia. The extended portion of the forecast will
likely be a beautiful period in the mountains as well as along
the coast. It wouldn`t be too surprising to see some coastal
areas make a run at 60 degrees on Friday. After what transpired
in December, perhaps we`ve earned a welcome break. 27
&&
.AVIATION...
Southwest flow aloft will transition more westerly
tonight into early Tuesday as an upper ridge builds further into
Western Washington. VFR/MVFR cigs early this morning with rain
primarily from King County northwards and along the Olympic
Peninsula. Predominantly low-end VFR to MVFR for much of the area
through today, with IFR/LIFR confined to the coast. Cigs will lower
further again tonight. Gusty southerly winds will continue,
especially for the coast, and terminals from PAE northwards. Gusts
may reach 30 to 35 kts at times for BLI this morning. Otherwise,
winds will slowly subside tonight.
KSEA...Low-end VFR conditions early this morning. Cigs are expected
to range from low-end VFR to MVFR through this afternoon (mainly
between 020-035). Cigs may lower further towards IFR late tonight
into Tuesday morning. S/SW surface winds ranging 8 to 12 kts with
occasional gusts to 15 to 20 kts through this afternoon. JD
&&
.MARINE...
A stalled frontal boundary across the northern half of the
waters will shift northward later today and weaken as surface
high pressure expands northward across the waters. Winds will
gradually ease across the waters through the day today. Broad
surface ridging will remain across the waters into midweek and a
frontal boundary will dissipate well offshore Wednesday afternoon.
Strong surface high pressure over the offshore waters will build
into the interior of British Columbia on Thursday as thermally
induced low pressure expands northward along the Oregon coast.
This will lead to a period of offshore flow toward the end of
the week. Apart from easterlies near gaps in coastal terrain,
this should be a relatively quiet period in terms of wind across
area waters.
Coastal seas will remain in double digits through Tuesday. They
may briefly dip below 10 feet Tuesday night or early Wednesday
before another decaying swell train pushes seas back above 10
feet. Seas will then subside to 5 to 7 feet at the conclusion
of the forecast period. 27
&&
.HYDROLOGY...
Steadier rain continues, mainly for the Olympics and North
Cascades. Additional precipitation amounts are expected to range
between 1 to 3 inches for the Cascades of Skagit and Whatcom
Counties, with 1 to 2 inches for the Cascades of Snohomish
County and the Olympics. Snow levels also range between 7000 to
8000 feet. The Skokomish River continues to rise, and is
forecast to approach (and potentially exceed) moderate flood
stage this morning. Additional rises on rivers are expected,
mainly in the aforementioned locations. The Skagit River in
particular continues to be monitored for potential minor river
flooding over the next day or two. Drier weather is then
expected later Tuesday through next weekend, with no additional
flooding expected. JD
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...None.
PZ...Small Craft Advisory until 4 AM PST Tuesday for Grays Harbor
Bar.
Gale Warning until 6 AM PST early this morning for Admiralty
Inlet-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-Northern
Inland Waters Including The San Juan Islands-West
Entrance U.S. Waters Strait Of Juan De Fuca.
Small Craft Advisory from 6 AM this morning to 10 PM PST this
evening for West Entrance U.S. Waters Strait Of Juan De
Fuca.
Small Craft Advisory until 10 AM PST this morning for Central
U.S. Waters Strait Of Juan De Fuca-Puget Sound and Hood
Canal.
Small Craft Advisory from 6 AM this morning to 1 PM PST this
afternoon for Admiralty Inlet-East Entrance U.S. Waters
Strait Of Juan De Fuca-Northern Inland Waters Including
The San Juan Islands.
Small Craft Advisory from 6 AM this morning to 4 AM PST
Tuesday 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
