Wind Advisory 26, NWS Seattle, WA

Area Forecast Discussion
National Weather Service Seattle WA
945 PM PST Thu Dec 8 2022

.SYNOPSIS...Scattered showers, gusty winds, and mountain snow
will decrease in coverage tonight. Another frontal system will
transverse into our region Friday evening into Saturday morning,
bringing lower snow levels and unsettled conditions. Cooler
temperatures look to stay, but drier conditions are more favorable
for the end of the weekend.

&&

.SHORT TERM /TONIGHT THROUGH SUNDAY/...A dissipating frontal
boundary associated with an upper level trough has been cruising
through our region this evening, with scattered rain showers
throughout the lowlands and snow showers within the mountains.
Coverage in precipitation has been slowly dwindling this evening
as the main shortwave fills and moves eastward out of the area.
Made a few minor adjustments to PoPs to account for this, and
adjusted temps and dew points in line with current obs. Fear not
as the next trough will quickly move into the region tomorrow,
thus, keeping the chance for scattered showers really through the
night into Friday.

As the aforementioned upper level trough shifts more inland on
Friday, our next front will move from the southeastern Gulf of
Alaska and look to cross through Western Washington Friday
evening. Another round of widespread precipitation looks to fill
in throughout the CWA, accompanied by breezy winds. The more
gustier winds look to be more impactful mainly near the coast,
along with portions of the Northern Interior.

For precipitation, confidence is growing more towards rain for
the most of the lowlands, with the exceptions being Hood Canal,
Kitsap Peninsula, and portions of western Whatcom county where
higher elevation snow might be observed. Even though the easterly
gradients are present in all of the aforementioned areas, the air
mass will just be marginally cold enough for snow, especially in
the Hood Canal / Kitsap Peninsula region. Could see a better
chance for snow within Western Whatcom county, up in the higher
hills near Bellingham, where colder air will be filtering in from
the north. High temperatures on Friday are generally going to be
into the 40s, with low temps staying in the low 30s.

At this time, accumulations do not look to be significant for any
lowland regions, but, if the cold air does filter down to the
surface for a longer period of time, overall snow totals could
range to 1 inch to possibly 1.5 inches from Friday night to
Saturday morning in the aforementioned areas. Otherwise, expect a
rain/snow mixture.

An upper level low looks to stay offshore on Saturday, so have
maintained PoPs in the forecast throughout the day as wrap-around
moisture could keep some scattered showers in our region.
Temperatures will be similar to Friday. Drier conditions will
start Sunday afternoon onwards, as the upper level low shifts
southward away from Washington. Ensembles and clusters are
agreeing with a ridge building into the Pacific Northwest into
Monday.

.LONG TERM /MONDAY THROUGH THURSDAY/...An upper level ridge looks
to stick around our region through the beginning of next week
with drier conditions likely. May see some light precip on the
coast on Tuesday, but overall, mostly dry elsewhere. Temperatures
look to remain below normal, with highs mostly within the low to
mid 40s, and low temperatures generally in the mid 20s to low 30s.

Mazurkiewicz/Davis

&&

.AVIATION...Southwest flow will continue through the night,
turning slightly more south-southeasterly into Friday morning. A
mix of MVFR and VFR ceilings currently will lower to primarily low
end MVFR in continued scattered showers overnight. So far, the
VFR CIGS had been primarily along the coast at KCLM and KHQM along
with KOLM where increased shower activity has kept things a
little more mixed. A brief period of VFR ceilings is possible
across interior areas Friday afternoon then increasing rain
spreads inland from the coast with ceilings deteriorating back to
MVFR. Guidance has sped the timing of the next round of rainfall a
touch, so this window is looking slimmer mostly from 18-23Z.
Gusty east to southeasterly surface winds develop Friday afternoon
through Friday night coastal areas and interior...especially KPAE
northward.

KSEA...MVFR ceilings with scattered showers moving off to the
east, though a few light showers are forecast to develop again
over the Puget Sound region around 09Z, so added mention of these
to the TAF. Increasing low level easterly flow could help dry air
mass enough to push ceilings back up to VFR for a period Friday
afternoon before they deteriorate back down to MVFR with
stratiform rain spreading back into the area by 00Z. Surface winds
S/SE 6 to 11 knots backing to E/SE 10 to 15 knots Friday
afternoon.

27/Davis

&&

.MARINE...The next vigorous front will move across the waters Friday
night into Saturday morning as an associated surface low deepens to
under 985 millibars as it approaches the north end of Vancouver
Island early Saturday morning. This will likely produce gale force
winds for the coastal waters, the Strait of Juan de Fuca, and
adjacent waters. Wind gusts may also approach storm force over the
coastal waters and the west entrance to the strait late Friday
night. Inherited headlines look good for now. Will recommend to
incoming shift to evaluate storm force potential with latest model
data. The surface low will gradually weaken and shift southward over
the offshore waters over the weekend allowing winds to ease. Weak
high pressure builds into the area early next week for quieter
conditions with the possible exception of breezy NE winds across the
Northern Inland Waters.

Coastal seas will remain hazardous through the weekend before
subsiding below 10 feet Monday and Tuesday. 27/18

&&

.HYDROLOGY...River flooding is not expected for the next 7 days.

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...None.
PZ...Small Craft Advisory until 4 PM PST Friday 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-Grays Harbor Bar.

     Small Craft Advisory until 4 AM PST Friday for West Entrance
     U.S. Waters Strait Of Juan De Fuca.

     Gale Watch from Friday afternoon through Saturday morning 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-West Entrance U.S.
     Waters Strait Of Juan De Fuca.

     Gale Watch from Friday evening through Saturday morning for
     Central U.S. Waters Strait Of Juan De Fuca-East Entrance
     U.S. Waters Strait Of Juan De Fuca-Northern Inland Waters
     Including The San Juan Islands.

&&