Brier Weather Station
Latitude N 47° 46' 49" Longitude W 122° 16' 48" Elevation 341 ft
142
FXUS66 KSEW 240941
AFDSEW
Area Forecast Discussion
National Weather Service Seattle WA
241 AM PDT Mon Aug 24 2026
.SYNOPSIS...
Upper level ridging building over the area today and Tuesday
will bring warm and dry conditions to western Washington. An
upper level low approaching the region midweek will bring the
return on onshore flow, cooler temperatures, and chances of
precipitation to the area. Upper level troughing will continue
to influence the region heading into the weekend, keeping
conditions cooler and cloudier across western Washington.
&&
.SHORT TERM /TODAY THROUGH WEDNESDAY/...
Upper level ridging will build over the Pacific Northwest
today, while a thermal trough at the surface builds northward
along the Washington coast. The ridge axis will shift inland
over the Intermountain West by Tuesday, while the thermal trough
at the surface also pushes inland. This pattern will bring a
warming and drying trend to western Washington for the start of
the week. Morning stratus will scatter quicker today and afternoon
highs will climb into the mid 70s to mid 80s across the interior
lowlands and into the mid 70s along the coast. A combination of
northerly and offshore flow will promote continued drying in
the low levels and may allow for some smoke from regional
wildfires over British Columbia and eastern Washington to make
its way back into the area. Tuesday is still on tap to be the
warmest day of the week, with afternoon high temperatures expected
to climb into the 80s across the majority of the interior and
into the low 90s across the Cascade valleys. This will reintroduce
Moderate HeatRisk to the valleys as well as the Everett-Seattle-
Tacoma metro areas.
A pattern change is expected around midweek as an upper level
low approaches the Pacific Northwest. This will bring the return
of onshore flow and cooler conditions to western Washington, as
well as reintroduce a few chances of showers to the area. Overall
QPF amounts look to remain light at this time, however cannot
rule out a few chances (around 10%) for thunderstorm development
along the coast as the low swings northeastward towards Vancouver
Island and Haida Gwaii and brings southwesterly flow aloft to
western Washington. Afternoon highs will generally be 5 to 10
degrees cooler than Tuesday`s and look to top out in the upper
70s to near 80 across the interior and in the mid 60s along the
coast.
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
Ensemble guidance remains in decent agreement with upper level
troughing lingering over the region through the second half of
the week. This will help maintain onshore flow across western
Washington and chances of light showers at times. Thunderstorms
will remain possible on Thursday as the aforementioned upper
level low swings through the region, but will primarily be
confined to the North Cascades. Temperatures will generally
trend to near to slightly below normal, with afternoon highs
topping out in the low to mid 70s across the interior and in the
low to mid 60s along the coast. Morning lows will generally be
in the 50s, but may fall into the 40s by later in the weekend.
14
&&
.AVIATION...
An upper level ridge will continue to build into the area
through today, with southwest flow aloft across western
Washington. Marine stratus along the coast this morning have
already brought coastal terminals down to LIFR (KHQM and KCLM).
Stratus pushing through the Strait will likely affect interior
terminals such KPAE, with IFR/LIFR ceilings this morning.
Additionally, we will likely see localized fog at terminals near
valleys that could bring deteriorated conditions early this
morning. Stratus and fog will burn off later this morning into
the afternoon with VFR returning by 18z/20z. Could see some
haze at times throughout the afternoon as well. N/NE winds 5 to
knots will increase slightly this afternoon, generally around 8
to 12 knots.
KSEA...VFR conditions early this morning at the terminal with NE
winds 8 to 12 knots. LIFR stratus continues to make its way
inland through the Strait - with latest guidance still
continuing to suggest a 10% chance of LIFR conditions at the
terminal, between 12z-17z. The confidence of stratus reaching
the terminal this morning is low, but the 10% probability
remains. Otherwise, VFR will continue at the terminal this
afternoon. North to northeast winds through the afternoon,
generally around 8 to 12 knots.
Mazurkiewicz
&&
.MARINE...
Surface high pressure remains over the coastal waters today and
will continue through Tuesday. Could see patchy fog over the
waters this morning as marine stratus continues to push onshore,
which may limit visibilities at times. Northerly winds will
increase over the coastal waters later this afternoon and
evening, with latest probabilities suggesting small craft
advisory gusts over the majority of the waters. A Small Craft
Advisory has been issued, particularly for gusts up to 25 kts.
Onshore flow looks to increase over the area Tuesday into
Wednesday, with a westerly push down the Strait of Juan de Fuca
that likely will warrant headlines.
Coastal seas 4 to 6 feet into Tuesday, with some areas,
especially in the outer coastal waters, seeing seas up to 7
feet. Additionally, with period of around 6 seconds, could see
choppy seas Monday afternoon and evening. Seas will subside to 3
to 5 feet through much of the week.
Mazurkiewicz
&&
.FIRE WEATHER...
Warmer and drier conditions are expected across western Washington
today and Tuesday as an upper level ridge builds into the region.
A thermal trough will also build northward along the coast today,
allowing for flow to turn offshore and promoting additional
drying in the low levels. Elevated fire weather conditions are
likely across the Cascades on Tuesday (the warmest day of the
week), with isolated spots expected to approach critical minimum
RH thresholds by dipping into the low to mid 20s. A pattern
change midweek will bring the return of onshore flow, cooler
temperatures, and chances of light precipitation to the area. A
10-20% chance of isolated thunderstorms will be possible,
primarily along the coast and North Cascades, Wednesday and
Thursday as the upper trough swings northeastward across the
region.
Upper level troughing then looks to remain over the area into
the weekend and should continue to promote onshore flow, excellent
overnight humidity recoveries, and cooler temperatures across
western Washington, which in turn will help mitigate fire weather
conditions through the weekend.
14
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...None.
PZ...Small Craft Advisory from 11 AM this morning to midnight PDT
tonight 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