Brier Weather Station
Latitude N 47° 46' 49" Longitude W 122° 16' 48" Elevation 341 ft
750
FXUS66 KSEW 301033
AFDSEW
Area Forecast Discussion
National Weather Service Seattle WA
333 AM PDT Sat May 30 2026
.SYNOPSIS...
Onshore flow will continue bringing continued cooler temperatures
this weekend. A warm and dry pattern moves in Monday through
Wednesday, with temperatures peaking on Tuesday as an area of
moderate HeatRisk builds over much of Western Washington. Late
next week likely features a return of cooler conditions with
occasional showers as the next upper trough arrives.
&&
.SHORT TERM /TODAY THROUGH MONDAY/...
Clouds over a weak convergence zone over the central and southern
Puget Sound lowlands will lift and scatter early this morning,
giving way to mostly clear skies by this afternoon.
With upper level troughing moving through the area, onshore flow
will remain relatively elevated, keeping temperatures seasonably
cool for this time of year. High temperatures will reach the low to
mid 60s. Low temperatures tonight will also be a touch cooler, in
the low to mid 40s. Some outlying areas may briefly dip into the
upper 30s. Mostly clear skies will continue to prevail across the
area on Sunday with western Washington on the west side of a
trough/east of a building ridge. High temperatures a bit warmer,
into the mid to upper 60s.
Monday will be the the start of a brief but rather abrupt warming
pattern as the ridge continues to build just offshore, allowing for
a weak thermal trough to get started along the coast. This will
start to bring weak offshore flow into the equation through the
overnight hours. High temperatures on Monday jump into the mid to
upper 70s. Low temperatures Monday night jump into the low 50s.
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
Ensembles remain in good agreement with a building ridge over
the region Tuesday and into Wednesday. This high pressure aloft
will bring a light offshore flow pattern as the air mass warms,
bringing temperatures into the 80s for the lowlands on Tuesday
as the thermal trough builds into the Puget Sound region. The
warmest locations in the South Sound could even make a run at
90 degrees. This will bring HeatRisk up into the Moderate
(Orange) category for much of the area away from the water from
Snohomish County all the way south through Lewis County. Areas
closest to the waters of Puget Sound will remain somewhat
cooler. While the offshore flow doesn`t look terribly strong at
this point, it will help to bring drier conditions with daytime
humidity values down toward 25% - see the fire weather section
for more details on this hazard. With the warmer conditions,
it`s worth noting that many area waters, especially those
flowing from the mountains, remain quite cold.
Temperatures then moderate a bit later in the week, with Minor
HeatRisk lingering as the ridge flattens and onshore flow
resumes across the region. While some rain showers will be
possible at times as this next disturbance approaches and moves
into the region, it doesn`t appear to bring much in the way of
meaningful rainfall amounts.
&&
.AVIATION...
Southwest flow continues aloft with upper level troughing over the
northwestern U.S. Much of the area is VFR with scattered low to mid
level clouds, as well as remnants of a convergence zone over the
central/southern Puget Sound area. Clouds may continue to fill in
throughout the morning, but guidance is maintaining that ceilings
will remain VFR, with relatively low (15-20% or less) probabilities
of MVFR ceilings this morning.
Therefore, will trend with VFR prevailing. Clouds look to break up
through the morning, allowing VFR conditions to prevail through the
TAF period. Most locations are seeing light and variable winds this
morning, with the exception of through and near the Strait where
west winds 10-15G20 kt continues. Winds during the day will
primarily be NW 5-10 kt, with gusts up to 20-25 kt at HQM and CLM
where the strongest winds will be.
KSEA...VFR conditions through the TAF period. CIGs around 030-040
kft will remain through 18Z this morning, but guidance remains
confident on remaining VFR (10% prob. of MVFR). E/SE winds around 5
kt will continue to veer towards NE after 18Z this morning, up to 5-
10 kt through the day.
62
&&
.MARINE...
Elevated onshore flow will continue through today across the area
waters as low pressure over the intermountain west gets pushed
eastward. Small Craft Advisory winds will continue to persist
through much of the day today. There will likely be a brief lull
through the latter half of the morning before winds begin to rise
once again this afternoon into tonight. Winds look to ease late
tonight into early Sunday morning as high pressure builds back over
the coastal waters. However, as that builds, northwesterly winds
will also begin to rise over the coastal waters, peaking Sunday
night and nearing SCA criteria, and easing into Monday. This will
also allow for waves to steepen and rise to around 7-9 ft during
this period before easing with the winds on Monday. High pressure
weekends and the gradients weaken on Monday and Tuesday for calmer
conditions to start the week. A frontal system looks to approach and
traverse the area waters mid-week, which at this time, looks to
increase onshore flow and may warrant additional headlines through
the Strait of Juan de Fuca as winds increase. Excluding the
aforementioned period Sunday into early Monday, seas look to remain
8 ft or less through the forecast period.
62
&&
.FIRE WEATHER...
An upper level ridge will setup a drier pattern on Monday and
Tuesday, with maximum temperatures reaching into the 80s (with a
few local spots touching 90). Expect a weak thermal low to build
north over the region, with some light offshore flow developing.
At this point, winds don`t appear too strong, but a few locations
near the Cascade gaps could see gusts to 20 mph. This will help
to bring drier conditions in to the area with daytime RHs down
approaching critical thresholds. This stretch appears short-
lived, with a resumption of onshore flow bringing higher
humidities for the second half of the week.
&&
.HYDROLOGY...
The daily hydrology discussion has ended until the start of the next
rainy season; it will only be updated during this time as
needed.
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...None.
PZ...Small Craft Advisory until midnight PDT tonight for Central
U.S. Waters Strait Of Juan De Fuca-East Entrance U.S.
Waters Strait Of Juan De Fuca.
&&
$$
NWS SEW Office Area Forecast Discussion