Brier Weather Station
Latitude N 47° 46' 49" Longitude W 122° 16' 48" Elevation 341 ft
878
FXUS66 KSEW 031013
AFDSEW
Area Forecast Discussion
National Weather Service Seattle WA
313 AM PDT Mon Aug 3 2026
.SYNOPSIS...
An upper level ridge will build offshore today and tonight then
move inland Tuesday and Wednesday. Thermally induced surface
trough developing over the area tonight will remain in place
through at least Wednesday night creating northerly flow in the
lower levels. This will pull some smoke over Western Washington. The
ridge will shift eastward later Thursday into Friday. Increasing
low level onshore flow at the end of the week with cooler
temperatures and less smoke.
&&
.SHORT TERM /TODAY THROUGH WEDNESDAY/...
Satellite imagery shows clear skies with the exception of low
clouds along the north coast and patchy fog over the Hood Canal
and South Puget Sound. Chilly morning for the first week of
August with Bremerton and Olympia in the 40s. Most of the
remainder of the area in the lower to mid 50s.
Upper level ridge building over Western Washington today with
the ridge axis offshore. Northerly flow aloft last night pulled
some upper level smoke down over the area ( you could see it at
sunset ) but with the flow aloft becoming more northwesterly
with the ridge building smoke in the upper levels will be kept
at a minimum. Patchy low clouds and fog will dissipate early
with sunny skies. Highs warming into the 70s and lower 80s.
Upper level ridge continuing to build tonight and Tuesday with
the ridge axis drifting towards the Pacific Northwest.
Thermally induced surface trough developing along the coast
tonight turning the low level flow northeasterly. This will most
likely pull low level smoke from the fires in Eastern
Washington into Western Washington by Tuesday morning. Smoke
will remain over the area during the day. The transition to
offshore flow in the lower levels warming high temperatures into
the 80s and lower 90s. Lows Monday night in the 50s. HeatRisk
moving into the moderate category for most locations away from
the immediate coast.
Upper level ridge axis moving over Western Washington later
Tuesday night into Wednesday with the thermally induced surface
trough over the area. Low level northeasterly flow will keep
low level smoke moving into Western Washington. Highs in the
80s to mid 90s. Lows in the mid 50s to lower 60s, cool enough to
prevent most of the area from major HeatRisk.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
Models showing good consistency for the latter half of the week
into the weekend. Upper level ridge axis over the area Wednesday
night moving east Thursday and Friday. Thermally induced surface
trough moves over the interior Thursday. Afternoon seabreezes
developing along the coast cooling high temperatures into the
lower to mid 70s. One more hot day over the interior with highs
similar to Wednesday, 80s to mid 90s. Moderate HeatRisk with a
20-40 percent chance of major HeatRisk Central and Southern
Puget Sound and Cascade foothills.
Increasing low level onshore flow Thursday night into Friday
with the ridge axis well to the east and the thermal induced
trough moving east of the Cascades. Low level onshore flow will
bring cooler temperatures and also push the low level smoke out
of the region. Highs in the mid 70s to mid 80s inland and upper
60s along the coast. Lows in the 50s and lower 60s.
Weak upper level trough settling over the area for the weekend
with varying degrees of low level onshore flow. Morning clouds
each day will give way to afternoon sunshine. Highs in the 70s
and lower 80s. Lows in the 50s. Felton
&&
.AVIATION...
Northwest flow aloft throughout the TAF period as an upper-ridge
axis sits offshore. Low-level flow has switched northerly - ushering
in drier air and leading to mostly clear skies (VFR) this morning.
Transient patchy fog has developed but any lingering should clear by
15-16z. VFR remaining throughout the day Monday into Tuesday as
well. Elevated smoke from region fires will arrive on Monday -
becoming more surface based on Tuesday.
KSEA...VFR throughout the TAF period. Elevated smoke will increase
today before becoming more surface-based into Tuesday. Can`t rule
out the chance for vis restrictions. NE surface winds 3-6 kt this
morning, increasing out of the N-NW this afternoon 5-10 kt with
gusts near 20 kt. Winds lighter and out of the NE 3-6 kt overnight
into Tuesday morning.
&&
.MARINE...
A strong surface high pressure will continue to remain offshore
throughout midweek as a thermally induced low pressure expands
northward along the interior coast. Winds over the waters will
continue to generally remain under small craft advisory levels.
The exception being, with the aforementioned presence of the
thermal trough over Western Washington, this could allow winds
over the outer coastal waters to approach low end advisory
levels this afternoon briefly and also, Tuesday afternoon
mainly in the southern inner coaster water zone.
The surface trough will move eastward Thursday and Thursday
night for increased onshore flow across the region, along with
potential headlines for westerlies in the Strait of Juan De
Fuca.
Coastal seas generally 4 to 6 feet through the first half of the
week. Seas look to gradually increase 6 to 8 feet during the
second half of the week.
Mazurkiewicz
&&
.FIRE WEATHER...
No changes as far as fire weather is concerned. Warming trend
beginning today peaking Thursday. Very low daytime RH values
throughout the CWA Tuesday through Thursday. The Cascades, Cascade
valleys, the adjacent lowlands of the Chehalis River Valley and
the south Puget Sound area will be of particular concern.
Minimum RH values each of those afternoons are expected to slip
into the teens. Wednesday and Thursday will be of particular
concern as minimum RH values could get as low as the low teens
to upper single digits. No significant winds or instability
expected during this time frame, so Red Flag criteria will most
likely not be met. Even without a red flag warning, with RHs
this low, any wind will contribute to fire spread and as such,
maximum caution is emphasized. Friday and beyond will see a much
more significant rebound in daytime RH values with low level
onshore flow. Felton
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...None.
PZ...Small Craft Advisory until 2 AM PDT early this morning for
Central U.S. Waters Strait Of Juan De Fuca-East Entrance
U.S. Waters Strait Of Juan De Fuca.
Small Craft Advisory until 3 AM PDT early this morning for
Coastal Waters From Cape Flattery To James Island 10 To
60 Nm-Coastal Waters From Cape Flattery To James Island
Out 10 Nm-Coastal Waters From James Island To Point
Grenville 10 To 60 Nm-Coastal Waters From James Island To
Point Grenville Out 10 Nm-Coastal Waters From Point
Grenville To Cape Shoalwater 10 To 60 Nm-Coastal Waters
From Point Grenville To Cape Shoalwater Out 10 Nm.
&&
$$
NWS SEW Office Area Forecast Discussion