Brier Weather Station
Latitude N 47° 46' 49" Longitude W 122° 16' 48" Elevation 341 ft
280
FXUS66 KSEW 291029
AFDSEW
Area Forecast Discussion
National Weather Service Seattle WA
329 AM PDT Thu Oct 29 2026
.SYNOPSIS...
Upper level low off Vancouver Island will slowly move south
ending up west of Hoquiam by late Friday afternoon. The low will
weaken Friday night and Saturday before moving inland as an
upper level trough Saturday night. Upper level ridge building
over Western Washington Sunday. The ridge will remain over the
area into the middle part of the week. A weak system will try an
move through the ridge Wednesday.
&&
.SHORT TERM /TODAY THROUGH SATURDAY/...
Satellite imagery shows upper level low off Vancouver Island
early this morning. Doppler radar has showers rotating around
the low over most of Western Washington at 3 AM/10Z.
Temperatures were in the 40s.
Upper level low slowly moving south in the next 36 hours.
Showers rotating around the low moving through Western
Washington at times. With the cool and unstable air mass over
the area some daytime "heating" could also produce showers late
in the afternoon/early evening hours. Snow levels remaining
around 3000 to 3500 feet but precipitation amounts will be light
leading to small new snow accumulations in the mountains. Highs
Thursday and Friday in the lower to mid 50s. Lows tonight in
the mid 30s to lower 40s.
With a stronger jet streak on the back side of the low, the low
will begin to elongate and weaken Friday night. This will turn
the flow aloft southerly which will keep the shower activity
closer to the center of the low confining pops to the coast
later Friday night. Lows in the mid 30s to lower 40s.
Low continuing to elongate and weaken Saturday with the jet
moving inland well south of the area. Shower activity remaining
confined to the coast. Highs in the mid 50s. Felton
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
Models in good agreement with elongated weakening upper level
trough moving through Western Washington Saturday night. Not
much moisture associated with the trough as it moves through the
area. Upper level ridge west of the trough building over
Western Washington Sunday into Sunday night. The ridge will
remain in place into the middle of the week. A weak warm front
will try and brush the coast the first part of the week but odds
are high the front will only produce some cloud cover. By
Wednesday another weak system will try and ride over the top of
the ridge. Like the warm front the odds are high it will only
produce some cloud cover for the area. Highs in the 50s. Lows in
the 30s.
With 0.15 inches at Seattle-Tacoma airport, Wednesday was the
4th day in a row with measurable rain at the airport. Last time
there was a streak this long was a 5 day streak May 12th through
the 16th. Felton
&&
.AVIATION...
An upper level trough will remain offshore of Western Washington
today into Friday, resulting in southwesterly flow aloft today
turning more southerly tonight. Surface winds largely light and
variable with speeds 5 kts or less, although some terminals are
reporting southerlies with slight variations to the southeast or
southwest with speeds slightly increased, ranging 4 to 8 kts. This
latter direction and speed will become more widespread by this
afternoon, although a return to some variability in direction is
possible by this evening.
The air mass is somewhat unstable which will maintain the chance for
showers throughout the TAF period. As such, a variety of cigs over W
WA at the time of this writing. IFR conditions have emerged at OLM
and PWT where low-level moisture often results in these conditions.
While some improvement into MVFR will be possible this morning,
lower cigs will linger here until the early afternoon. Some isolated
MVFR obs are also present, but the majority of terminals are
currently reporting VFR conditions. As the aforementioned showers
remain possible, occasional dips down into MVFR cannot be ruled out,
but overall the expectation is for widespread VFR conditions to
persist throughout the TAF period.
KSEA...VFR conditions with showers being reported on the 09Z ob.
While this may result in occasional dips down into high-end MVFR
during the early morning hours, the overall expectation is for VCSH
to persist but cigs remaining within VFR category. Overall
southeasterly winds expected for the TAF period, however models
remain consistent in a brief period around 00Z where north to
northwesterly winds may be possible. Speeds will remain consistent
throughout the period, ranging 4-8 kts.
18
&&
.MARINE...
Low pressure out over the coastal waters will allow for offshore
flow to persist into this weekend. A weak disturbance passing around
this low may allow for increased winds for the coastal waters at
times Friday and Saturday. Models have been shaky on speeds however,
with some speeds approaching SCA criteria depending on the model
run. At this time, will pass on any headline issuance but will
advise future shifts to continue to monitor this time frame.
Seas will continue to ease, currently running 5 to 7 ft, subsiding
slightly further to 4 to 6 ft by this evening before bottoming out
at 3 to 5 ft this weekend. Looking ahead, seas will likely build
early next week back to around 10 ft with the arrival of a long
period swell into the coastal waters.
18
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...None.
PZ...None.
&&
$$
NWS SEW Office Area Forecast Discussion