Brier Weather Station
Latitude N 47° 46' 49" Longitude W 122° 16' 48" Elevation 341 ft
062
FXUS66 KSEW 011749
AFDSEW
Area Forecast Discussion
National Weather Service Seattle WA
949 AM PST Thu Jan 1 2026
.SYNOPSIS...Systems spinning out of an upper level trough
offshore moving through Western Washington later tonight into
Friday morning and again later Saturday into Sunday morning.
Upper level trough moving through Western Washington Monday.
Another system reaching the area later Tuesday into Wednesday.
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.SHORT TERM /TODAY THROUGH SATURDAY/...Mid and high clouds
continue to increase this morning ahead of a frontal system that
will move northwards into the area later today. Fog continues to
dissipate ahead of the front, and the Dense Fog Advisory has
been allowed to expire. No major changes to the forecast this
morning. Previous discussion below:
A weather system will approach from the south this afternoon
with a small increase in the low level flow lifting the fog into
a low cloud cover. Rain out ahead of the approaching system
reaching the southern portion of the area late afternoon. Under
cloudy skies highs will remain in the 40s.
Rain spreading over Western Washington from the south overnight.
Snow levels 5000 to 7000 feet. Easterly gradients will trap
cold air in the passes creating the potential for freezing rain
especially in Snoqualmie pass. Snow amounts with the southerly
flow aloft will be light but with the freezing rain potential
winter weather advisory will remain in effect for the Snoqualmie
pass area into early Friday morning. Lows tonight in the mid 30s
to lower 40s.
Front dissipating over the area Friday with rain tapering off in
the afternoon. Easterly gradients weakening with the cold air
trapped in the passes scouring out in the morning ending the
freezing rain threat. Highs near 50.
Rain out ahead of the next system spinning out of the upper
level trough offshore reaching the area Friday night. Trough
offshore moving south and east into Saturday stalling the front
over Western Washington Saturday. Rainfall amounts only a
quarter of an inch or less. Snow levels remaining at least 5000
feet keeping the precipitation in the passes as rain.
Coastal flooding is possible during high tides Friday morning.
Better chance for coastal flooding over the weekend with higher
astronomical tides, as well as the combination of lower
pressure and increased winds and waves. At this time, minor to
moderate coastal flooding is expected for both Saturday and
Sunday. Major coastal flooding cannot be ruled out for the
coast this weekend, particularly due to the stronger winds and
increasing seas. Water levels look to rise up to a maximum of
around 2 to 2.5 feet above ground level for most locations along
the water this weekend. Felton
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...Extended models
still having trouble with the placement of the surface low
associated with the front Saturday night into Sunday morning.
One set of solutions has the low moving by to the west along
127W through Sunday morning. Another set of solutions has the
low closer to the area with the low moving inland over Vancouver
Island Sunday morning and a weak lee side surface low northeast
of the Olympics. Olympia to Bellingham gradient as high as plus
7 mb on some of the solutions. If the windier solutions win out
a wind advisory will be likely for Sunday morning over the
interior. Even with the windier solutions the winds do not last
very long with the low weakening and moving northeast. Upper
level trough moving through Monday keeping at least chance pops
in the forecast. Another system arriving later in the week with
a majority of the solutions favoring a Tuesday night or
Wednesday arrival. Felton
&&
.AVIATION...Southwest flow aloft continues as an upper level
disturbance lifting northward out of broad trough offshore
approaches the region. Light low level offshore flow continues with
widespread low level moisture trapped across the interior lowlands.
LIFR/IFR ceilings and surface visibilities below 1SM has been
observed but improvement is being met as the morning progress. Mid
and high level moisture is increasing with IFR or low MVFR ceilings
in light rain expected across the region this evening.
KSEA...MVFR/IFR conditions in fog/stratus with visibility so far in
this morning`s update. High and mid level clouds will increase above
it. There is low confidence in a brief period of VFR midday before
rain develops after 00Z with ceilings lowering back to low MVFR or
occasional IFR this evening. Surface winds light and variable.
27/41
&&
.MARINE...A system will move up from the south reaching the
area tonight into Friday morning. A stronger frontal system will
move through the waters Saturday into Sunday morning for
increasing winds and seas. Another system will arrive Monday.
Small craft advisory winds over the waters later Saturday night into
Sunday with gales possible over the interior waters Sunday morning.
Small craft advisory winds also possible over the coastal waters
again Tuesday into Wednesday.
Seas 5 to 8 feet building to 10 to 14 feet Saturday. Seas subsiding
back down below 10 feet Monday. Felton
&&
.HYDROLOGY...Multiple frontal systems moving through Western
Washington into the weekend. The Skokomish River, starting from
elevated levels, is forecast to approach flood stage on Sunday,
before receding early next week. No additional river flooding
is expected into next week. JD/Felton
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...Winter Weather Advisory from 1 PM this afternoon to 7 AM PST
Friday for Cascades of Southern King County.
Coastal Flood Advisory until noon PST today for Grays Harbor
County Coast.
PZ...Dense Fog Advisory until noon PST today for Admiralty Inlet-
Northern Inland Waters Including The San Juan Islands-
Puget Sound and Hood Canal.
&&
$$
NWS SEW Office Area Forecast Discussion