Brier Weather Station
Latitude N 47° 46' 49" Longitude W 122° 16' 48" Elevation 341 ft
823
FXUS66 KSEW 272211
AFDSEW
Area Forecast Discussion
National Weather Service Seattle WA
311 PM PDT Thu Aug 27 2026
.SYNOPSIS...
An upper-trough will swing a couple of disturbances into the
region Thursday through Saturday. Brief ridging is in the offing
to begin next week but the pattern is forecast to reopen by
Tuesday as additional troughing takes aim. A well-ogranized
system looks to arrive around midweek with the potential for
widespread rainfall. Cooler than average temperatures are
favored throughout this time.
&&
.SHORT TERM /TONIGHT THROUGH SATURDAY NIGHT/...
The first of a series of upper-lows has swept through western
Washington earlier today. Light shower activity has resulted
along with breezy winds. Latest KATX/KLGX scans show shower
coverage mainly over the coast, Olympic Peninsula and Cascade
mountains along with a smattering over the southwest interior.
200-400 j/kg of surface based CAPE over the northern half of the
CWA is being highlighted by HREF this afternoon. So with that,
can`t rule out a strike of lightning or two before the evening.
Tonight, conditions are slated to trend drier as we`ll be in
between disturbances. Overnight lows are forecast to drop into
the 50s.
Quasi-zonal flow aloft on Friday as models have the next
impending upper-low looming off the coast of British Columbia.
Mostly dry conditions during the day on Friday (barring a few
showers) however, guidance have 850 mb winds converging over
Puget Sound Friday night. A PSCZ is favored to develop around
this time across both King and Snohomish counties with
measurable rainfall a probability into the early morning hours
on Saturday. The aforementioned upper-low is slated to arrive
on Saturday morning as well with more widespread rain showers
across western Washington. A 10-20% chance of thunder is in the
forecast across the CWA with the highest probabilities over the
Cascades. Precipitation will gradually dry out Saturday night
as subsidence provided via transient ridging builds in to start
the new week. Highs throughout the short-term ranging between
the lower 60s to lower 70s with overnight lows in the 50s but
can`t rule out a few 40s in the southwest interior.
&&
.LONG TERM /SUNDAY THROUGH THURSDAY/...
As mentioned, brief upper-ridging Sunday and Monday with drier
conditions. Then, the next upper-trough will dig over the NE
PAC and sit right off the PNW coast by Monday evening. Given
latest guidance, it`s associated upper-low will track south of
the area into Oregon but we could get side swiped with showers
on Tuesday. Then, a more organized disturbance is slated to
arrive Wednesday and lead into Thursday. This feature has the
potential to bring widespread rainfall and well-below average
temperatures as the region will begin to get a taste of fall.
41
&&
.AVIATION...
Generally VFR this afternoon with areas of lingering MVFR in low
clouds. Showers and isolated thunderstorm activity will continue to
progress eastward across western Washington through the evening,
mainly impacting the coastal terminals and terminals near the Canada
border. Shower activity will produce localized MVFR conditions. Mid
level clouds will stick around through the evening with continued
VFR conditions, with another marine push overnight and residual
moisture expected to bring in an expansive low stratus deck
affecting most terminals early Friday morning. As a result,
widespread MVFR to IFR is expected, with localized LIFR possible
along the coast and over the Kitsap Peninsula. Breezy south to
southwest winds will continue through the afternoon with gusts to 20
kt, with decreasing speeds overnight.
KSEA...VFR this afternoon with mid level clouds and breezy
southwesterly winds with gusts to 20 kt at times. Conditions will
calm into the evening, with increasing chances for MVFR conditions
developing early Friday morning as low stratus expands over the
Puget Sound. Improvement back to VFR expected by Friday afternoon,
with light winds.
15
&&
.MARINE...
A weak frontal system will continue to move over the coastal waters
today. Breezy south to southwesterly winds have picked up as a
result, with localized gusts up to 30 kt in northern portions of the
Hood Canal, producing wind waves up to 4 feet. As a result, a Small
Craft Advisory has been issued through this afternoon. The strongest
winds in this advisory will be in the Hood Canal area, though
isolated SCA wind gusts elsewhere are possible through the afternoon.
Weak systems will continue to move over the coastal waters through
the weekend, maintaining onshore flow and periodic westerly pushes
through the Strait of Juan De Fuca. The westerly push Friday looks
to reach Small Craft strength The push on Friday is expected to
reach Small Craft strength, and a Small Craft Advisory has been
issued. Another weaker westerly push is expected Saturday evening
before winds become generally benign over area waters through the
remainder of the weekend.
Seas will remain around 4 to 6 feet through the weekend.
15
&&
.FIRE WEATHER...
Onshore flow, cooler temperatures, and increasing RHs will persist
into next week. There still remains an isolated threat for
thunderstorms this afternoon and Saturday afternoon. For today, the
threat is primarily over the Northern Cascades. As for Saturday, the
threat expands from the Northern Cascades into the Central Cascades.
Shall a thunderstorm develop, wetting rains are unlikely and
lightning may pose a hazard that could lead to new fire starts.
Additionally, thunderstorms could produce erratic and gusty outflow
winds over existing fires. A weather system towards the middle
of next week may bring wetting rains to the area.
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...None.
PZ...Small Craft Advisory until 5 PM PDT this afternoon for
Admiralty Inlet-Puget Sound and Hood Canal.
&&
$$
NWS SEW Office Area Forecast Discussion