Brier Weather Station
Latitude N 47° 46' 49" Longitude W 122° 16' 48" Elevation 341 ft
283
FXUS66 KSEW 062301
AFDSEW
Area Forecast Discussion
National Weather Service Seattle WA
401 PM PDT Thu Aug 6 2026
.SYNOPSIS...
Warm conditions through Friday, followed by a gradual cooldown to
near-normal temperatures by the end of the week. Upper level ridge
axis and thermally induced trough over Western Washington today will
push east tonight. The backside of the ridge will remain over
the region through Saturday. Upper level flow becomes zonal on
Sunday, continuing through at least midweek. Uncertainty in the
forecast towards the second part of the week.
&&
.SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/...
Another warm and smoky day for Western Washington. Latest obs show
temperatures in the mid/upper 80s to low 90s along the interior and
70s along the coast. Visibilities range between 5 to 9 miles.
The ridge axis over Western Washington will move into Eastern
Washington tonight, along with the thermal trough. A gradual
cooldown expected to start Friday as the back end of the ridge
moves across the area through Saturday. However, temperatures
will remain slightly elevated east of the I-5 corridor for the
interior and foothills. Low temperatures in the upper 50s to low
60s and high temperatures will be in the mid/upper 80s to low
90s will have Moderate HeatRisk for these locations.
Consequently the heat advisory has been extended through Friday
night. As for locations west of I-5, onshore flow will help cool
temperatures into the upper 60s to low 70s for the coast and
low to mid 80s for interior locations.
With the thermal trough having pushed east, onshore flow will help
gradually mitigate smoke impacts tonight through Friday for the
interior portions. However, some elevated some may not completely
clear out until later Friday or early Saturday.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
Long-term guidance favors zonal flow aloft to establish over Western
Washington through at least early next week. By midweek solutions
begin to disagree on the forecast. Although, majority of members
continue to trend toward zonal flow on Wednesday. As for Thursday,
some solutions hint at an upper level ridge forming over Western
Washington, while other solutions favor a weak trough over the
region.
29
&&
.AVIATION...
VFR cigs with visibility impacts from smoke this afternoon. Onshore
flow will continue to mitigate smoke impacts near the surface
tonight and into tomorrow. Slant-wise visibility impacts should also
gradually improve this afternoon into tomorrow as smoke aloft
disperses. Another marine push expected tonight, bringing IFR/LIFR
conditions to the coast and portions of the southwest interior
towards SHN. Latest guidance suggests the stratus will attempt to
push east towards the Kitsap Peninsula and OLM, keeping a slight
chance(30%)for MVFR cigs overnight. Brief improvement along the
coast in the afternoon, before conditions deteriorate again in the
evening. Generally NW winds 4-6 kt will become light to calm
overnight at interior terminals. Winds shift SW Friday morning.
KSEA...VFR conditions will prevail today and Friday. Wildfire smoke
continues to impact surface visibility to around 6SM. Smoke
conditions at the surface and aloft should gradually improve tonight
into tomorrow with onshore flow. NW winds this afternoon 4-6 kt,
becoming light overnight. Winds shift SW Friday morning and increase
to 5-7 kt in the afternoon.
29
&&
.MARINE...
An area of strong high pressure will continue to strengthen
over the NE Pacific and expand into Washington`s waters. It will
remain over area waters into early next week. Increasing
onshore flow will lead to diurnal pushes likely (70-90% chance)
meeting small craft thresholds through the Strait of Juan de
Fuca each evening starting on Friday. Guidance continues to back
off the potential (15% chance) for gales on Saturday; rather
guidance is suggesting a high-end small craft event. In
addition, there is a 20-30% chance for gales on Tuesday through
the Strait of Juan de Fuca. Headlines also possible this
weekend for the coastal waters. Winds will increase across the
coastal waters starting Saturday, bringing a 40-70% chance for
small craft winds to the southernmost zones. Seas will also be
steep this Saturday with combined seas of 6-8 feet and a
dominant period around 7 seconds.
29
&&
.FIRE WEATHER...
Elevated fire weather conditions across the area
today and tomorrow with above average temperatures in concert with
dry conditions. Minimum RH values are lowering into the mid 10s to
lower 20s in Cascade zones 658/659 and surrounding valleys. Olympic
zones 661 and 652 zones have seen their lowest RHs earlier this
morning with values in the 20s for location such as Hurricane Ridge.
While no significant wind or instability is expected today for a red
flag warning, maximum caution over new fire starts still should be
emphasized.
The thermally induced trough is currently shifting eastward. As a
result, a gentle push of onshore flow is expected this evening into
Friday but not strong enough to completely alleviate concerns.
Onshore flow will increase in strength Saturday into into early next
week with cooler temperatures and increased moisture with much
better humidity recoveries across the region.
Wildfire smoke over the area today could cause localized impacts to
fire operations.
41
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...Heat Advisory until 10 PM PDT this evening for Eastern Kitsap
County-Eastern Strait of Juan de Fuca-Foothills and
Valleys of Thurston and Lewis Counties-Foothills of the
Western and Southern Olympic Peninsula-Island County-Lake
Crescent Area Including US 101-Lower Chehalis River
Valley-Lowlands of Lewis and Southern Thurston Counties-
Middle Chehalis River Valley-Northern Hood Canal-Olympia
and Southern Puget Sound-Port Townsend Area-San Juan
County-Southern Hood Canal-Willapa and Black Hills.
Air Quality Alert until 5 PM PDT this afternoon for Cascades
of Whatcom and Skagit Counties-Foothills of the Western
and Southern Olympic Peninsula-Grays Harbor County Coast-
Lower Chehalis River Valley-Lowlands of Western Whatcom
County-Middle Chehalis River Valley-Olympia and Southern
Puget Sound-Olympics-Southern Hood Canal.
Air Quality Alert until 8 AM PDT Friday for Cascades of Pierce
and Lewis Counties-Cascades of Snohomish and Northern
King Counties-Cascades of Southern King County-City of
Seattle-Downtown Everett / Marysville Area-Eastern Kitsap
County-Eastside-Foothills and Valleys of Central King
County-Foothills and Valleys of Pierce and Southern King
Counties-Foothills and Valleys of Snohomish and Northern
King Counties-Foothills and Valleys of the North Cascades-
Lowlands of Pierce and Southern King Counties-Lowlands of
Western Skagit and Northwestern Snohomish Counties-
Northern Hood Canal-Shoreline / Lynnwood / South Everett
Area.
Heat Advisory until 10 PM PDT Friday for City of Seattle-
Downtown Everett / Marysville Area-Eastside-Foothills and
Valleys of Central King County-Foothills and Valleys of
Pierce and Southern King Counties-Foothills and Valleys
of Snohomish and Northern King Counties-Foothills and
Valleys of the North Cascades-Lowlands of Pierce and
Southern King Counties-Lowlands of Western Skagit and
Northwestern Snohomish Counties-Lowlands of Western
Whatcom County-Shoreline / Lynnwood / South Everett Area.
Air Quality Alert until 11 PM PDT this evening for Foothills
and Valleys of Thurston and Lewis Counties-Lowlands of
Lewis and Southern Thurston Counties-Willapa and Black
Hills.
PZ...None.
&&
$$
NWS SEW Office Area Forecast Discussion