Brier Weather Station
Latitude N 47° 46' 49" Longitude W 122° 16' 48" Elevation 341 ft
487
FXUS66 KSEW 301557
AFDSEW
Area Forecast Discussion
National Weather Service Seattle WA
857 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 are starting to lift and scatter, 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 aloft will continue today as upper
level troughing remains the dominant influence over the
northwestern U.S. Much of the area this morning is VFR with
scattered low to mid level clouds, mainly from remnants of a
convergence zone over the central and southern Puget Sound area.
A few ceilings have dipped to MVFR across the central Sound
terminals this morning, but expect these lower ceilings to be
relatively short-lived as satellite already indicates low clouds
scattering out across the area. Clouds will continue to break
up through the morning hours. MVFR terminals should improve back
to VFR by mid to late morning, with VFR conditions expected to
prevail through the remainder of the day. Most locations are
seeing light and variable winds this morning, with the exception
of KCLM near the Strait where westerly winds continue at 8-12
kt and gust to near 20 kt at times. Winds for many terminals
will switch to the northwest by this afternoon and persist at
5-10 kt, with gusts up to 20-25 kt possible at HQM and CLM where
the strongest winds will be.
KSEA...The terminal has briefly dipped down into MVFR this
morning, with cigs between 2500-3000 ft. Expect MVFR conditions
to be short-lived, with VFR conditions returning by mid to late
morning. Conditions will then remain VFR through the remainder
of the TAF period. Southerly winds around 5 kt will become
northerly after 18Z this morning, and increase to 5- 10 kt
through the day.
62/14
&&
.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 along the
central and eastern Strait of Juan de Fuca. There will likely be
a brief lull in winds through the latter half of the morning
before winds begin to rise once again this afternoon into
tonight. Winds will then 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 and
gradients will then 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.
62/14
&&
.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