Brier Weather Station
Latitude N 47° 46' 49" Longitude W 122° 16' 48" Elevation 341 ft
231
FXUS66 KSEW 070333
AFDSEW
Area Forecast Discussion
National Weather Service Seattle WA
833 PM 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.
Warm conditions are expected throughout the week, with morning
clouds and patchy fog, giving way to sunny afternoons. Rain
chances increase into Friday as a front moves through. Cooler
conditions arrive this weekend through early next week.
&&
.SHORT TERM /TONIGHT THROUGH THURSDAY NIGHT/...
Evening update: Remaining fog/stratus in the east Strait of
Juan de Fuca area is beginning to increase in coverage this
evening, with a shallow fog bank moving down Puget Sound. A few
areas (particularly around Mukilteo) have already dropped down
to a quarter of a mile in spots. Fog development will be
monitored overnight for potential headlines. The remainder of
the short-term discussion below is valid for the evening update.
High pressure at the surface remains offshore with lower pressure
inland. A zonal flow pattern with a weak ridge overhead and a jet
streak in southern Canada will continue to funnel the onshore
pattern through midweek. Another round of fog and stratus will
form tonight into Wednesday morning. The north/south interior
and Olympics are the favored areas to see the lowest cloud
decks/visibilities in the morning. and will clear by early
afternoon. Probabilities for fog on Thursday morning are
considerably less, but can`t rule out a few valley areas seeing
development. Temperatures in this period will continue to remain
mild, and slowly increase up to Thursday with a few spots even
seeing highs into the low 70s. Overnight lows will range from
the upper 40s to low 50s. Winds will remain out of the northwest
at around 5-10 mph for most areas.
HPR
&&
.LONG TERM /FRIDAY THROUGH TUESDAY/...
The next frontal system will sweep across the region later
Friday through Saturday. While still some spread within the
ensemble guidance, around 60-70% of members suggest a fairly
deep upper trough moving through the region. This will bring
some increased winds across the area ahead of the system on
Friday, with rain continuing into Saturday. That said, rainfall
amounts aren`t looking too impressive with totals around a tenth
to a quarter of an inch through late Saturday. Colder air then
settles into the region this weekend. Two things to consider
with this for the weekend into the start of next week: 1) Any
additional showers could bring some light snow accumulations
above around 4,500 ft or so. 2) For the foothills and outlying
locations, overnight lows could begin to dip down into the 30s.
While confidence isn`t high, those with agricultural concerns
should keep an close eye on the forecast for potential frost
headlines for the start of next week. Cullen
&&
.AVIATION...
A flat upper ridge remains over region with westerly flow aloft. The
low level flow is light northerly or weakly offshore. Stratus never
fully cleared across the northern portions of Puget Sound and is
expanding southward this evening. With weak surface gradients and
already narrow temperature dew point spreads, the low levels are
primed for widespread (albeit shallow) formation of LIFR low cloud
and restricted surface visibility overnight into Wednesday morning.
These conditions will persist into late morning before VFR returns
across the area 18Z-20Z.
KSEA...LIFR clouds are spreading southward across Puget Sound this
evening and, as such, timing for LIFR conditions has been moved
forward several hours. Conditions will be favorable for additional
fog and low clouds to form in place as a light northerly surface
gradient weakens overnight. Predominant LIFR ceilings are expected
by around 08Z or 09Z with surface visibilities falling below 1SM at
times. These conditions are expected to hang around through 18Z
before gradually lifting and scattering out Wednesday afternoon.
Surface winds light northerly becoming N/NW 6 to 8 knots Wednesday
afternoon.
27
&&
.MARINE...
High pressure over the waters will remain for the next few days.
In the short term, the primary marine impact will be continued
fog over portions of the waters. Improvement over the eastern
Strait of Juan de Fuca and adjacent waters has been quite slow,
which will likely result in widespread visibility less than 3 NM
again late tonight through early tomorrow morning. Confidence
remains a little lower in how widespread the dense fog will be,
so will continue to evaluate the need for an advisory as it
expands tonight.
Otherwise, a building thermal trough along the Oregon coast will
make its way north to the Washington coast, bringing northerly
winds to the coastal waters. The strongest winds look to remain
south of the local area, but there`s around a 20-30% chance of
some gusts to 25 kt across the inner coastal waters off of Grays
Harbor on Wednesday and especially Thursday afternoon.
Similarly, some marginal advisory gusts through the central
Strait may develop Thursday as winds return onshore. Chances
remain too low for any advisories at this time, but it remains
worth watching. More significant marine weather is expected
Friday as the next frontal system reaches the coastal waters,
pushing inland through early Saturday. This will likely (>80%
chance) bring widespread advisory winds to the coastal waters
and the Strait of Juan de Fuca, with seas building to at least
8-9 ft over the coastal waters. Current probabilities of
reaching 10 ft remain around 60% for the end of the week. Cullen
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...None.
PZ...None.
&&
$$
NWS SEW Office Area Forecast Discussion