156
FXUS66 KSEW 101124
AFDSEW

Area Forecast Discussion
National Weather Service Seattle WA
324 AM PST Fri Jan 10 2025

.SYNOPSIS...An upper level trough will continue to push into the
Pacific Northwest today, bringing in breezy winds alongside
lowland rain and mountain snow. Convergence zone showers will set
up over the central Cascades tonight, with continued showers
lingering through the weekend under moist northwest flow. Drier
conditions are forecast to return next week as high pressure
rebuilds over the western US.

&&

.SHORT TERM /TODAY THROUGH SUNDAY/...A frontal system will
continue to move inland this morning and sweep across the Pacific
Northwest throughout the day today, bringing in lowland rain and
mountain snow alongside breezy post-frontal onshore winds. Snow
levels will fall to 3000 ft by late Friday, resulting in snow
accumulation through Snoqualmie and Stevens Passes. Confidence is
high that Puget Sound Convergence Zone showers will form over the
central Cascades later today into early Saturday morning which
will locally enhance snowfall amounts. Latest model guidance
shows roughly 7 inches of snow through Snoqualmie Pass and 11
inches through Stevens Pass enhanced by convergence zone shower
activity, and a Winter Weather Advisory remains in effect through
early Saturday morning.

Lower elevations will see drying throughout the day Saturday, with
lingering snow showers over the Cascades under moist northwest
flow aloft. Snow levels will dip to roughly 2000 ft, though any
additional snow accumulation amounts on Saturday will be light.
The rest of the region will see cloudy skies with some afternoon
sun breaks and highs in the mid to upper 40s.

As high pressure rebuilds offshore, a ripple in the periphery of
the ridge will move southward across the region on Sunday morning,
maintaining light showers over higher terrain. Conditions will
clear out by the afternoon, giving way to mostly sunny skies and
slightly cooler highs in the mid 40s.

.LONG TERM /MONDAY THROUGH THURSDAY/...Long range models continue
to favor high pressure building over western Washington through
much of next week, allowing for drier and warmer conditions. Weak
forcing and residual moisture will likely allow for rounds of low
stratus and patchy fog around the Puget Sound lowlands early
Monday and Tuesday mornings with mostly sunny skies returning
each afternoon. The ridge is favored to break down towards the end
of next week as moist zonal flow returns, but significant impacts
are not expected with this pattern change.

Lindeman

&&

.AVIATION...Front moving through the area this morning. Post
frontal onshore flow this afternoon and tonight with convergence
zone over Snohomish County. Westerly flow aloft becoming
northwesterly this afternoon as post frontal upper level trough
moves through Western Washington.

Ceilings lowering to MVFR this morning and remaining MVFR into the
afternoon hours. Improving trend after 02z with VFR ceilings for a
few hours until the ceilings lower back down to MVFR after 09z.

KSEA...Ceilings lowering to MVFR 13z-15z this morning and
remaining MVFR into the afternoon hours. Improving trend after 00z
with VFR ceilings with convergence zone north of the terminal.
Ceilings lowering back down to MVFR after 09z. Southerly winds
around 10 kt becoming southwest 12 to 18 kt around 18z.

Felton

&&

.MARINE...A frontal system will move through the waters
this morning. bringing increased winds and seas. Broad surface
ridging will rebuild offshore this afternoon into tonight. This
ridge will expand into area waters over the weekend for a
relatively quiet period into early next week.

Post frontal gales in the Strait of Juan de Fuca beginning late
this morning and continuing into the evening hours. Small craft
advisory winds for the remainder of the waters except the Puget
Sound into tonight. Small craft advisory conditions continuing
over the Coastal Waters into Saturday night.

Seas building to 12 to 16 ft today subsiding under 10 ft Sunday.

Felton

&&

.HYDROLOGY...No river flooding is expected over the next 7 days.

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...Winter Weather Advisory from 6 AM this morning to 6 AM PST
     Saturday for West Slopes North Central Cascades and Passes.

PZ...Small Craft Advisory from 4 AM early this morning to 10 AM PST
     Saturday for Grays Harbor Bar.

     Small Craft Advisory until 10 AM PST Saturday 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.

     Small Craft Advisory from 7 AM this morning to 7 AM PST Saturday
     for Central U.S. Waters Strait Of Juan De Fuca-East
     Entrance U.S. Waters Strait Of Juan De Fuca.

     Small Craft Advisory from 1 PM this afternoon to 7 AM PST
     Saturday for Northern Inland Waters Including The San Juan
     Islands.

     Small Craft Advisory from 10 AM this morning to 10 PM PST this
     evening for Admiralty Inlet.

&&

$$