Brier Weather Station
Latitude N 47° 46' 49" Longitude W 122° 16' 48" Elevation 341 ft
836
FXUS66 KSEW 280311
AFDSEW
Area Forecast Discussion
National Weather Service Seattle WA
810 PM PDT Thu Aug 27 2026
.SYNOPSIS...
An upper-trough will swing a couple of disturbances into the region
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/...
Shower activity has mostly fizzled out from an already pretty
scattered pattern over W WA earlier this afternoon...although the
last vestiges can be found over the North Cascades. Inherited
forecast remains on track and thusly, no evening updates are
required. For additional forecast details, please refer to the
Previous Discussion section below. 18
From Previous Discussion...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...
West-southwest flow aloft continues through Friday with troughing
over Western Washington. VFR cigs this evening with widespread mid
level clouds. A few showers will linger into Friday, however most
terminals will remain dry through Friday afternoon. Stratus will
develop tonight into Friday morning for MVFR/IFR cigs for most
terminals. Localized LIFR possible along the coast as well as across
the Kitsap Peninsula. Cigs will slowly improve into the afternoon.
South to southwest winds through Friday morning will become more
northerly for a few sites from King CO northwards by Friday
afternoon.
KSEA...VFR cigs this evening with mid level clouds. Cigs will lower
into MVFR between 10-12z and remain MVFR through midday before cigs
slowly lift into VFR. There remains a 20 to 25% probability for IFR
cigs Friday AM as well, mainly between 12 to 17z. South winds into
Friday afternoon may briefly transition to N/NW Friday evening. JD
&&
.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 from 2 PM to 11 PM PDT Friday for Central
U.S. Waters Strait Of Juan De Fuca.
&&
$$
NWS SEW Office Area Forecast Discussion