Gale Warning 1, NWS Seattle, WA

Area Forecast Discussion
National Weather Service Seattle WA
332 AM PST Sat Jan 1 2022

.SYNOPSIS...Upper level ridge over the area weakening today with a
warm front moving by to the north tonight. Cold front moving down
British Columbia coast stalling over Western Washington Sunday
into Sunday night. The front will move south of the area Monday
morning. Next system moving inland over Oregon Tuesday. Warm front
approaching from the southwest moving into Western Washington
Wednesday night and Thursday with another system arriving Friday.

&&

.SHORT TERM /TODAY THROUGH MONDAY/...Satellite imagery shows high
clouds embedded in the northwesterly flow aloft moving into the
area at 3 am/11z. The mostly clear skies earlier tonight combined
with the snow cover allowed temperatures to drop into the single
digits in some locations. Bellingham dropped down to 6 degrees
around 1130 pm last night but with the increasing cloud cover the
temperature has already recovered to 18. At 3 am temperatures
were mostly in the teens and lower 20s.

Weak upper level ridge over Western Washington continuing to
weaken today as a warm front starts to move over the top of the
ridge. Increasing clouds for the remainder of the area not
already cloudy this morning with mostly cloudy skies continuing
through this afternoon. Ridge keeping the precipitation
associated with the warm front to the north with just a chance of
rain along the North Coast this afternoon. Highs will mostly be
in the mid 30s except along the coast where highs will be near 40.

Upper level ridge gone by tonight with warm front moving into
Southern British Columbia. Surface gradients increasing over
Western Washington. Model 925 mb winds along the coast and over
the Northwest Interior in the 30 to 40 knot range by 12z Sunday.
Will convert the High Wind Watch to a wind advisory beginning at
06z/10 pm tonight for the coast and Northwest Interior. Frontal
system still well north of the area by 12z Sunday keeping
locations in the interior from about Seattle southward dry into
Sunday morning. Lows will be near freezing but these temperatures
will occur ahead of the precipitation. Temperatures warming
overnight into the mid and upper 30s.

Cold front stalling Sunday with upper level trough offshore
digging south. Front which is east/west oriented Sunday morning
becoming more north/south oriented by Sunday afternoon. This will
slow down the southeast movement of the front with the front still
northwest of the area by late Sunday afternoon. This stalling of
the front will keep windy conditions along the coast and over the
Northwest Interior going during the day. Rain spreading over
Western Washington Sunday morning with rain continuing into the
afternoon. Highs in the lower to mid 40s.

Cold front moving slowly through Western Washington Sunday night
with the front still not clear of the area by 12z Monday. Heavy
snow in the mountains with 12 to 18 inches of new snow just in the
overnight period Sunday night into Monday morning. The winter
storm watch will be converted to a winter storm warning for the
Cascades and Olympics.

Front moving south into Oregon Monday morning. As has been the
case for the last few nights both the GFS and ECMWF ensembles have
some solutions with lowland snow Monday morning behind the front.
While the GFS continues to show 1000-850 mb thickness values below
1300 meters, the 00z ECMWF now has only the Northwest Interior
below 1300 meters Monday morning. Both models continue to show
significant southerly winds at 925 mb ( 20 to 30 knots ). The air
mass will be cooling down with the snow level in the 1500-2000
foot range ahead and with the front. The southerly winds at 925 mb
should keep the snow level off the surface Monday morning. It
will take some enhanced precipitation rates to drive the snow
level below 500 feet and right now the models are not really
showing that scenario. Will stay with the 500-1000 foot snow
levels behind the front Monday morning which still means some of
the higher locations in the metro area could see a little snow.
Highs Monday back down to near 40.

.LONG TERM /TUESDAY THROUGH FRIDAY/...Models in good agreement
with the next system moving inland over Oregon Tuesday late
morning into the afternoon. Snow levels once again low Tuesday
morning, near 500 feet, but moisture will be limited with the
system moving inland well to the south. Can't rule out snow
showers Tuesday morning but if any occur snow accumulations should
be light. Showers continuing into the afternoon hours with highs
remaining cool, near 40.

Possible break in the action Wednesday with Western Washington in
between systems. Warm front lifting up from the southwest will
help warm the air aloft Wednesday night into Thursday. Will have
to be on the lookout for a possible overrunning scenario
especially over the Northwest Interior with the front approaching
from the south drawing cooler air out of British Columbia into
Whatcom county. Next system arriving Friday with continued warming
aloft and surface gradients turning onshore resulting in a more
typical rainy day with highs in the mid 40s.

&&

.AVIATION...Westerly flow aloft expected today with south to southeasterly
prevailing surface winds, generally AOB 10kts. Patchy fzfg this
morning expected in the vicinity of the south Sound, primarily
affecting KOLM where vsbys have fluctuated between 1 and 3 SM over
the past few hours. Expect fog to quickly mix out after sunrise this
morning with VFR conditions prevailing at all TAF sites under SCT to
BKN CIGS.

KSEA...VFR conditions through the period under SCT to BKN CIGS.
CIGs will gradually lower through the day, falling to around 5K FT
around 00Z this afternoon. Southeasterly prevailing wind
generally 4 to 8 kts through the period.

Pullin

&&

.MARINE...A warm front associated with a deep surface low
northwest of Haida Gwaii will lift northward across the coastal
waters today into Sunday then stall, leading to increasing
southerly winds through the day. A strong front will approach and
sweep across area waters Sunday into Monday, yielding gales
offshore and across the inland waters. Calmer conditions will
prevail behind this system, with lighter winds and falling seas
early next week.

Seas subsiding today before again building sharply on Sunday with a
mix of west swell and a significant southerly wind wave/fresh swell
component. Seas will again peak between 10 to 14 feet Sunday night
through Monday before decreasing Tuesday into midweek.

Pullin/Cullen

&&

.HYDROLOGY...Transition to warmer, wetter pattern in the middle
of next week could result in the Skokomish River in Mason County
going over flood stage late in the week. Outside of the Skokomish,
river flooding not expected in the next 7 days, but significant
rises may also push some points on the Chehalis and Newaukum River
close to flood stage late next week.

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...Winter Storm Watch from Sunday afternoon through Monday
     afternoon for Cascades of Pierce and Lewis Counties-
     Cascades of Snohomish and King Counties-Cascades of Whatcom
     and Skagit Counties.

     High Wind Watch from late tonight through Sunday evening for
     Admiralty Inlet Area-Central Coast-North Coast-San Juan
     County-Western Skagit County-Western Whatcom County.

     Winter Storm Watch from Sunday morning through Monday afternoon
     for Olympics.

PZ...Gale Watch from this afternoon through Sunday afternoon 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.

     Small Craft Advisory until 4 PM PST this afternoon 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 late tonight through Sunday 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 10 AM this morning to midnight PST
     tonight 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 noon today to 4 PM PST Sunday for
     Central U.S. Waters Strait Of Juan De Fuca-West Entrance
     U.S. Waters Strait Of Juan De Fuca.

     Small Craft Advisory from 10 AM this morning to 4 AM PST Sunday
     for Puget Sound and Hood Canal.

&&

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