Brier Weather Station
Latitude N 47° 46' 49" Longitude W 122° 16' 48" Elevation 341 ft
432
FXUS66 KSEW 060839
AFDSEW
Area Forecast Discussion
National Weather Service Seattle WA
139 AM PDT Tue Oct 6 2026
.SYNOPSIS...
Mostly zonal flow will persist over western Washington as high
pressure amplifies over the Great Basin region to the south.
Seasonably warm conditions are expected throughout the week,
with morning clouds and patchy fog, giving way to sunny
afternoons. Rain chances increase into Friday, but the incoming
system doesn`t appear to be particularly strong.
&&
.SHORT TERM /TODAY THROUGH THURSDAY/...
Stratus and fog are expected this morning again as temperatures
and dewpoints near one another and lightly onshore flow
persists. Early morning observations across the region indicate
visibilities as low as a quarter of a mile along the coast and
through the Strait of Juan de Fuca. This will continue inland
throughout the morning, with in-situ development in the Puget
Sound region. Stratus and fog that develops will likely burn
off by the early afternoon. Gradients become more northerly by
this afternoon into Wednesday, dampening the widespread stratus
and fog potential through the middle of the week, though the
threat of patchy fog development will continue.
Given the zonal flow to weakly amplified high pressure in
Washington, temperatures will remain on the mild to warm side.
Through midweek, temperatures will be in the upper 60s, with a
bump in temperatures come Thursday where the low 70s are
expected due to weakly offshore flow.
&&
.LONG TERM /THURSDAY NIGHT THROUGH SUNDAY/...
By late in the week, the influence of the western CONUS ridge
weakens slightly and may allow for broad troughing over the NE
Pacific. The ensembles generally keeping the ridge in place
through Thursday, with some deviation toward a trough by Friday
and the weekend. There is a bit more consensus on broader
troughing over the weekend, but low placement is not generally
agreed upon. For sensible weather in western Washington, this
brings a weak system into the area on Friday, with light rain
amounts expected into Saturday. At this time, Sunday looks
drier.
Accompanying the troughing will be a dip in the low temperatures
over the weekend. Lows will be in the low to mid 40s throughout
Puget Sound, dipping into the upper 30s in the Cascades and
adjacent foothills.
21
&&
.AVIATION...
A mostly flat upper level ridge will remain overhead through
the TAF period, promoting westerly flow aloft. Low level flow
remains lightly onshore, but will transition to more northerly
throughout the day. Widespread low cloud and/or fog formation is
expected for much of the lowlands this morning, with LIFR ceilings
and reduced surface visibility below 3SM expected to become more
widespread by 12Z. Low clouds will gradually lift and scatter
for most areas between 19-21Z for a return to VFR conditions.
Another round of low clouds/fog will be possible on Wednesday
morning.
KSEA...VFR conditions will deteriorate after 09Z, with LIFR
ceilings and visibilities below 2SM expected to develop at the
terminal by 12Z. Low ceilings and visibilities will hang around
through most of the morning, with improvement towards VFR
expected between 19-21Z. Winds this morning are light out of
the north/northeast at 5 kt or less, but will increase to 5-10
kt this afternoon after 18Z.
14
&&
.MARINE...
High pressure will remain situated over the coastal waters with
lower pressure inland over the next several days. Areas of fog
are likely to develop over the waters again this morning and
will continue to be likely over the next few days. Latest HREF
guidance indicates the the greatest probabilities (between 45-65%)
of visibilities dropping below 1 NM this morning are along the
central and eastern Strait of Juan de Fuca, Admiralty Inlet, and
the Puget Sound waters. Expect visibilities to improve again into
the afternoon as fog slowly dissipates.
A thermal trough expanding northward along the Oregon coast
today and along the Washington coast Wednesday will turn flow
more northerly across the waters through Thursday. Periods of
gusty northerly winds may develop across the southern coastal
water zones at times this evening into Wednesday, but expect the
winds to primarily remain between 15-20 kt at this time. Seas
will largely range between 4-8 ft through Thursday.
Onshore flow will then resume Thursday night into Friday. A
frontal system approaching the area waters from the north Friday
into Saturday will likely bring small craft strength winds to
the coastal waters and the Strait of Juan de Fuca. Seas will
build in the system`s wake Friday night into Saturday, with GEFS
guidance showing a 50-60% probability of seas exceeding 9 ft.
14
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...None.
PZ...None.
&&
$$
NWS SEW Office Area Forecast Discussion