Brier Weather Station
Latitude N 47° 46' 49" Longitude W 122° 16' 48" Elevation 341 ft
122
FXUS66 KSEW 052247
AFDSEW
Area Forecast Discussion
National Weather Service Seattle WA
347 PM PDT Wed Aug 5 2026
.SYNOPSIS...
An upper level ridge will remain over Western Washington through
Thursday. The ridge axis will push east late Thursday night. A
thermally induced trough along the coast will finally move inland
Thursday and push east late that night, allowing onshore flow to be
reinstated. A more zonal upper level pattern develops toward the
end of the week, bringing a gradual cooldown towards near normal
temperatures.
&&
.SHORT TERM /TONIGHT THROUGH FRIDAY NIGHT/...
Smoke at the surface continues to impact Western Washington this
afternoon affecting visibility and air quality. Latest weather obs
show the lowest visibilities towards Bellingham, with visibility at
2 miles. As for other locations, visibility ranges between 6 to 9
miles. Warmer today with temperatures continuing to climb this
afternoon into the mid 80s to 90s in the interior and 70s along the
coast.
An upper level ridge will remain situated over Western Washington
through Thursday. The ridge axis will push into Eastern Washington
late Thursday into early Friday morning. As the ridge progresses
east, it will weaken and flatten leading to zonal flow aloft.
Another warm day expected on Thursday with widespread Moderate
HeatRisk across the region. Temperatures are forecasted to peak
in the mid 80s and low 90s along the interior. A gradual
cooldown expected to start Friday, but temperatures still look
to remain on the warm side on Friday. Guidance suggests there
is a 70% chance or greater for Moderate HeatRisk along Central
Puget Sound and the Cascade foothills. Low temperatures are also
expected to be on the warmer side, offering little relief
overnight.
The thermal trough along the coast is expected to push inland
tomorrow and east of the area late Thursday. Onshore flow should
help improve smoke conditions as early as late Thursday along the
coast and Friday for the interior. 29
29
&&
.LONG TERM /SATURDAY THROUGH WEDNESDAY/...
The gradual cooling trend continues this weekend, with temperatures
returning to near seasonal normals as ensemble guidance remains in
good agreement that the ridge continues to flatten out and a more
zonal flow pattern returning to the region. Onshore flow continues
into the region and will become a little stronger, which should push
the majority of remaining smoke aloft east of the area. Saturday
likely remains a bit warmer with lingering Moderate HeatRisk favored
in the Seattle metro area, but a return to Minor HeatRisk area-wide
follows for the first part of next week. Expect that onshore flow
will bring some morning clouds each day, but scattering clouds into
the afternoon. Ensemble guidance does begin to present a wider range
of possibilities toward the middle of next week, but the majority
(around 75+%) of members suggest no precipitation and near normal
temperatures through the long term period.
&&
.AVIATION...
Upper level ridge traversing the area tomorrow maintain
west/northwesterly flow aloft. Most terminals are VFR this afternoon,
through some terminals are seeing lower flight categories due to
limitations in horizontal visibility from smoke, particularly BLI.
Areas of smoke will continue this afternoon before the low- level
onshore flow starts to kick in and forecast concentrations of smoke
begin to slowly decrease. This will improve horizontal visibility but
slant-wise visibilities will likely remain limited. Marine stratus
is expected to redevelop along the coast tonight, but since the
onshore flow is relatively weak, it should struggle to get much
farther east of OLM/CLM. Stratus will likely bring in IFR to LIFR
conditions, otherwise, terminals look to remain VFR with clear
skies, outside of any lingering smoke. Winds light north-northwest
will remain light and variable to calm overnight. Winds remain
mostly light northwesterly tomorrow, around 5 kt.
KSEA...VFR conditions expected through the TAF period with clear
skies. Smoke continues to limit horizontal visibility to around 6 SM
with additional slant-wise limitations. Smoke concentrations should
begin to improve tonight. Northwest winds 6-8 kt this afternoon
should turn northeast after around 04Z and decrease to 5 kt or less.
Winds remain light but turn northwesterly during the day Thursday.
/62
&&
.MARINE...
High pressure offshore and a thermally induced trough along the
coastline. The thermal induced trough will push inland
tomorrow, reinstating onshore flow across area waters. A small
craft advisory remains in effect for the outer coastal waters
for steep seas between 6-8 ft with a dominant period of 6 to 7
seconds. With onshore flow resuming, strong westerlies meeting
small craft thresholds are likely across the Strait of Juan de
Fuca starting Friday evening and continuing into next week. The
strongest push through the Strait will be Saturday evening.
Latest guidance suggests high-end small craft winds. The chance
for gales has slightly trended down to 15%. Seas will build this
weekend just shy of 10 feet, then decrease going into Monday.
29
&&
.FIRE WEATHER...
Elevated fire weather concerns across the area the next couple of
days with warm and dry weather. Smoke layer taking a few degrees, up
to 1ten degrees off the maximum temperatures which in turn makes for
higher minimum relative humidity values in the afternoon. Instead of
dropping into the teens in the drier locations minimum RH values
staying around 30 percent the next couple of days. While no
significant wind or instability is expected through Thursday, hat
could change Friday and maximum caution over new fire starts still
should be emphasized through this time period.
The thermally induced trough will shift into Eastern Washington
Thursday night though it looks to move slowly and may take until
Friday to completely transit the area. Some uncertainty still
remains over potential instability and incoming wind in combination
with the eastward movement of the thermal trough which may briefly
promote fire growth late Thursday into early Friday. Hot and dry
conditions may hold Friday east of the Puget Sound. Increased
onshore flow Saturday into Sunday is expected to bring cooler
temperatures and increased moisture with healthier humidity
recoveries across the region.
In addition, north to east winds through Thursday will bring in
wildfire smoke from Eastern Washington and British Columbia. This
will cause localized impacts to fire operations at times.
Felton/JBB
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...Heat Advisory until 10 PM PDT Thursday for City of Seattle-
Downtown Everett / Marysville Area-Eastern Kitsap County-
Eastern Strait of Juan de Fuca-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 Thurston and Lewis Counties-Foothills and
Valleys of the North Cascades-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-
Lowlands of Pierce and Southern King Counties-Lowlands of
Western Skagit and Northwestern Snohomish Counties-
Lowlands of Western Whatcom County-Middle Chehalis River
Valley-Northern Hood Canal-Olympia and Southern Puget
Sound-Port Townsend Area-San Juan County-Shoreline /
Lynnwood / South Everett Area-Southern Hood Canal-Willapa
and Black Hills.
Air Quality Alert until 5 PM PDT Thursday for Cascades of
Pierce and Lewis Counties-Cascades of Snohomish and
Northern King Counties-Cascades of Southern King County-
Cascades of Whatcom and Skagit Counties-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 Thurston and Lewis
Counties-Foothills and Valleys of the North Cascades-
Foothills of the Western and Southern Olympic Peninsula-
Grays Harbor County Coast-Lower Chehalis River Valley-
Lowlands of Lewis and Southern Thurston Counties-Lowlands
of Pierce and Southern King Counties-Lowlands of Western
Skagit and Northwestern Snohomish Counties-Lowlands of
Western Whatcom County-Middle Chehalis River Valley-
Northern Hood Canal-Olympia and Southern Puget Sound-
Olympics-Shoreline / Lynnwood / South Everett Area-
Southern Hood Canal-Willapa and Black Hills.
PZ...Small Craft Advisory until 5 AM PDT Thursday for Coastal
Waters From Cape Flattery To James Island 10 To 60 Nm-
Coastal Waters From James Island To Point Grenville 10 To
60 Nm-Coastal Waters From Point Grenville To Cape
Shoalwater 10 To 60 Nm.
&&
$$
NWS SEW Office Area Forecast Discussion