145
FXUS66 KSEW 081636
AFDSEW

Area Forecast Discussion
National Weather Service Seattle WA
836 AM PST Wed Jan 8 2025

.UPDATE...Overcast skies across the majority of Western Washington
this morning, but should give way to some sunshine later this
afternoon. The forecast remains on track and no significant
updates are needed at this time. Please refer to the previous
forecast discussion and updated aviation discussion below.

&&

.SYNOPSIS...Conditions will briefly dry out mid-week under high
pressure with rounds of morning fog and low stratus. The next
round of precipitation will arrive on Friday as a trough moves
through the Pacific Northwest, with showers favored to continue
through the weekend under moist northwest flow. Drier conditions
are forecast to return by early next week as high pressure
rebuilds.

&&

.SHORT TERM /TODAY THROUGH FRIDAY/...A weak frontal system will
continue to dissipate as it moves eastward this morning, spreading
a round of light showers across western Washington. Shower
activity will taper off throughout the morning as high pressure
builds inland, giving way to drier and warmer conditions by the
afternoon with plentiful sun breaks. Highs are on track to peak
near the 50 degree mark across the lowlands.

An upper level ridge will continue to amplify towards the Pacific
coast through Thursday, allowing for dry and mild conditions to
prevail. Residual moisture and light winds will likely give way to
another round of fog and low stratus Thursday morning before
conditions improve in the afternoon. Highs will once again peak
near the 50 degree mark across the lowlands, with slightly warmer
temperatures along the coast and through the Cascade foothills.

The next frontal system will sweep across the Pacific Northwest
on Friday, bringing in lowland rain and mountain snow alongside
breezy westerly winds. Snow levels will fall to 3000-4000 ft by
Friday afternoon, resulting in a few inches of snow accumulation
through Snoqualmie and Stevens Passes. Forecast models also
continue to highlight the potential for the development of Puget
Sound Convergence Zone showers over the central Cascades late
Friday which may locally enhance snowfall amounts.

.LONG TERM /SATURDAY THROUGH TUESDAY/...Moist northwest flow aloft
maintains the chance for continued light showers over higher
terrain heading into the weekend as high pressure rebuilds
offshore. The ridge axis will shift inland by early next week,
allowing dry conditions to settle into the region with
temperatures peaking a few degrees below normal.

15

.LONG TERM /SATURDAY THROUGH TUESDAY/...Moist northwest flow aloft
maintains the chance for continued light showers over higher
terrain heading into the weekend as high pressure rebuilds
offshore. The ridge axis will shift inland by early next week,
allowing dry conditions to settle into the region with
temperatures peaking a few degrees below normal.

15

&&

.AVIATION...Westerly flow aloft this morning will become
northwesterly later today as a dissipating front over the area exits
and an upper level ridge rebuilds into the region. Areas of MVFR
ceilings inland and along the coast will lift by late morning with
VFR conditions expected areawide this afternoon. Clearing skies late
today along with light surface winds out of the north will be
favorable for the formation of areas of LIFR/IFR in low clouds and
patchy fog on Thursday morning.

KSEA...MVFR Ceilings just over 2,000 feet will lift through the
morning, and start scattering out by late afternoon. Winds have
flipped to the north and will be up to 6-8 kt late this morning into
the afternoon. Evening clearing and rather light surface winds
overnight point toward favorable conditions for LIFR in fog/low
clouds Thursday AM.  27/HPR

&&

.MARINE...
Surface ridging over the coastal and offshore waters will
shift inland tonight and Thursday for offshore flow. The next
frontal system will reach the coastal waters late Thursday night and
sweep onshore Friday morning. Broad surface high pressure will
rebuild across the offshore waters this weekend then gradually shift
inland early next week. Headlines for winds ahead of and behind the
front on Friday are expected for most of the waters. Coastal seas
will straddle the 10 foot threshold early today before subsiding.
Seas jump back into the 11 to 15 foot range with the late week front
and remain near 10 feet through the upcoming weekend.   27

&&

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

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...None.
PZ...Small Craft Advisory until 10 AM PST this 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.

&&

$$