Brier Weather Station
Latitude N 47° 46' 49" Longitude W 122° 16' 48" Elevation 341 ft
293
FXUS66 KSEW 281010
AFDSEW
Area Forecast Discussion
National Weather Service Seattle WA
310 AM PDT Wed Oct 28 2026
.SYNOPSIS...
Upper level low near Vancouver Island this morning will not move
much in the next couple of days ending up off the Washington
coast Friday. The low will weaken to a trough Saturday and move
inland Saturday night. Upper level ridge building offshore
Sunday will move over Western Washington Monday and Tuesday.
&&
.SHORT TERM /TODAY THROUGH FRIDAY/...
Satellite imagery shows cool upper level low centered near
Vancouver Island early this morning. Wave clouds over and to the
east of the Cascades good indication of some decent winds
aloft. Camp Muir at 10,000 feet on Mount Rainier reporting 49
mph with gusts to 66 mph. Showers rotating around the low over
much of Western Washington at 3 AM/10Z. Temperatures were in
the 40s.
Upper level low not moving much today. Showers will continue to
spin around the low and move into Western Washington. This
afternoon 500 mb temperatures near -30C, convective temperatures
in the mid 50s, lifted indexes near 0 and lapse rates around
7.5 C/KM. All this adds up to a chance of thunderstorms late in
the afternoon. Snow levels in the 3000 to 3500 foot range.
Heaviest snowfall occurring early this morning. Paradise on
Mount Rainier reported 2 inches of new snow between midnight and
1 AM ( thanks to our friends at the Northwest Avalanche Center
for the data ). New snow amounts today will be heaviest around
Mount Rainier, up to 6 inches. Just a couple more inches of new
snow elsewhere in the Cascades. Winter Weather Advisory will
remain up until 5 pm this afternoon. Cool day in the lowlands
with the clouds and showers. Highs in the lower to mid 50s.
Little change in the pattern tonight into Thursday. Upper level
low drifts slowly south and west ending up west of KUIL by 00z
Friday. Showers continuing to rotate around the low moving into
Western Washington. The low does weaken a touch with the winds
aloft easing. This will weaken the orographics in the mountains
so even though the shower activity will continue new snow
amounts will decrease. Light additional accumulations in the
forecast. Lows tonight in the mid 30s to lower 40s. Highs
Thursday again in the lower to mid 50s.
Low drifting south Thursday night and Friday with the flow aloft
becoming southwesterly. This is another negative for much in
the way of accumulating new snow in the mountains even as snow
levels remain in the 3000 to 3500 foot range. For the lowlands a
continuation of a chance of showers/showers likely forecast.
Lows in the mid 30s to lower 40s. Highs in the lower to mid 50s.
Felton
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
Models in pretty good agreement with the low weakening and
continuing to drift south Friday night into Saturday. Flow aloft
becoming southerly and with the jet moving inland to the south
pops becoming confined to the western half of the area by
Saturday afternoon. Low weakens to an upper level trough and
moves inland Saturday night. Upper level ridge building off the
coast Sunday moving over Western Washington Sunday night and
Monday. The ridge will weaken a little Tuesday. Still a few
ensemble solutions with a warm front sneaking over the ridge
nicking the coast Sunday night and Monday so will have slight
chance pops for the north coast. With the ridge aloft and the
low level flow turning light offshore the potential for fog
exists both Monday and Tuesday morning. Some of the ensemble
solutions indicating the ridge will be a little dirty with high
cloud cover getting into the area. With this in mind have only
gone for patchy or areas of fog both mornings. Highs mostly in
the mid 50s. Lows in the mid 30s to lower 40s Saturday and
Sunday cooling to the upper 20s and 30s Monday and Tuesday.
Felton
&&
.AVIATION...Northwesterly flow this morning shifting more westerly
to southwesterly by this evening. Surface winds will remain south to
southwesterly throughout the TAF period, although speeds will start
from breezy with some occasional gusts to settling down into the 5-
10 kt range this afternoon and evening.
Widespread rainfall this morning resulting in lower cigs with
widespread MVFR to IFR conditions at most terminals. However, some
terminals such as HQM, OLM and CLM are reporting VFR conditions as
of 2 AM PDT. That said, locations under rainfall will likely remain
under the lower cigs while those that see precip move on do have the
potential to improve up a category or two. Ultimately, given how
widespread precip is, would plan for MVFR or lower conditions until
mid to late morning before conditions begin to improve back to VFR
by this afternoon. Once VFR conditions are met, will likely remain
there for the remainder of the TAF period, with an exception
possibly being OLM due to their fog-prone nature.
KSEA...MVFR conditions in place and with precip still upstream from
the terminal, would expect MVFR to linger into the late morning
hours. Should start to see improvement to VFR conditions by 21Z this
afternoon, even though lingering showers will be a possibility.
Breezy winds mainly in the 8-12 kt range with occasional gusts up to
20 kt in place for much of the morning, but as per above discussion,
should see speeds ease this afternoon to 5-10 kts. Direction is
expected to remain south to southwesterly throughout the TAF period.
18
&&
.MARINE...Northwesterly winds along the outer coastal waters
will linger into early this morning, but will ease after 5 AM PDT
this morning. Same for seas. As such, timing on inherited headlines
looks good and will run its course unaltered.
Following suit, winds will also ease across the inland waters as the
accompanying surface low drops into the area and tracks southward
along the coastal waters. As it does so, this will allow for flow to
turn back offshore, with offshore flow persisting the second part of
the week.
Seas easing throughout the day, ranging 7 to 10 ft early this
morning favoring 6 to 9 ft by noon today. 5 to 7 ft waves are
expected by tonight and remain there into Thursday. Further
subsiding of seas is expected, with 4 to 6 ft expected by the
weekend.
18
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...Winter Weather Advisory until 5 PM PDT this afternoon for
Cascades of Pierce and Lewis Counties-Cascades of
Snohomish and Northern King Counties-Cascades of Southern
King County-Cascades of Whatcom and Skagit Counties.
PZ...Small Craft Advisory until 5 AM PDT early this morning for
Coastal Waters From Cape Flattery To James Island 10 To
60 Nm-Coastal Waters From James Island To Point Grenville
10 To 60 Nm-Coastal Waters From Point Grenville To Cape
Shoalwater 10 To 60 Nm.
&&
$$
NWS SEW Office Area Forecast Discussion