Brier Weather Station
Latitude N 47° 46' 49" Longitude W 122° 16' 48" Elevation 341 ft
595
FXUS66 KSEW 031020
AFDSEW
Area Forecast Discussion
National Weather Service Seattle WA
320 AM PDT Wed Jun 3 2026
.SYNOPSIS...
Upper level trough moving through Western Washington today
bringing much cooler weather to the area. Brief upper level
ridge later tonight into Thursday. Upper level low moving out
of Gulf of Alaska moving down the British Columbia coast
Thursday night and Friday. Weak system spinning out of low
moving into the area Friday. Upper level low reaching Western
Washington Saturday moving east Saturday night. Another upper
level trough arriving Monday.
&&
.SHORT TERM /TODAY THROUGH FRIDAY/...
Satellite imagery shows cloudy skies over Western Washington
with a negatively tilted trough off the coast. Mild morning
with the cloud cover, temperatures at 3 am/10z in the mid 50s
to mid 60s.
Upper level trough moving through Western Washington today. The
trough will be weakening as it moves inland for just a chance of
showers over portions of the area. Low level flow turned onshore
last night and onshore flow will continue today. Main story will
be the much cooler temperatures. Highs today in the 60s and
lower 70s. In some cases a 20 degree drop from Tuesday.
Upper level trough moving east tonight. Low level onshore flow
increasing behind the trough keeping skies at least mostly
cloudy. Convergence zone forming overnight over Snohomish county
giving the county a chance of light showers/drizzle. Lows in the
upper 40s to mid 50s.
Thursday an in between day with an upper level trough to the
east and the upper level low just starting to exit the Gulf of
Alaska. Convergence zone remaining intact in the morning hours
keeping showers in the forecast for Snohomish County and
Northern King county. Weak upper level ridge out ahead of the
upper level low moving over Western Washington in the afternoon
while the low level flow goes light. Even with afternoon
sunshine highs mostly in the 60s.
Upper level ridge moving east Thursday night. Low level onshore
flow returning bringing the marine layer back into the interior.
Lows in the mid 40s to mid 50s.
Upper level shortwave spinning out of the approaching upper
level low moving into Western Washington Friday returning at
least a chance of showers back to the forecast. Air mass
slightly unstable Friday afternoon. A thunderstorm can`t be
ruled out but chances are low, 20 percent or less. Cloud cover
and showers keeping highs near 60. Felton
&&
.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
Shortwave dissipating over Western Washington Friday night.
Upper level low following Saturday keeping showers in the
forecast. Increasing instablilty with the upper level low right
over the top of the area in the afternoon. Chance of
thunderstorms over all of Western Washington Saturday afternoon
in addition to widespread showers. Highs once again near 60.
Upper level low moving east Saturday night with drying
northwesterly flow aloft behind the low. Clearing skies along
with the remnants of the cooler air mass will make for a chilly
Sunday morning. Lows in the colder locations dropping into the
upper 30s. Elsewhere lows in the lower to mid 40s.
Weak upper level ridge moving through Sunday but plenty of low
level moisture hanging around making for a mostly cloudy/partly
sunny day. Highs warming up into the 60s.
Another upper level trough moving into Western Washington
Monday for more cool and showery weather. The trough will
linger into Tuesday keeping a chance of showers in the forecast.
We had an increase in interest in the 90 day outlook with the
calendar turning to June. The current 90 day outlook has a
60-70 percent chance of above normal temperatures for the June
through August timeframe in Western Washington. In Seattle we
have had above normal temperatures in June through August for
13 years in a row. The last year June through August had below
normal temperatures was 2012 ( 0.7 degrees below normal ). It
was close in 2024 with temperatures only 0.3 degrees above
normal. The warmest June through August in the above normal
streak was 2015 where temperatures were 5.0 degrees above
normal. The remainder of the years range from 1.1 degrees to 3.2
degrees above normal. Felton
&&
.AVIATION...
A cold front and trough will advance inland today as
high pressure moves east. Expect flow aloft to increase from the
west as the onshore gradient increases. Satellite is showing high
clouds filling in, which will lower this morning, but remain VFR for
all but the immediate Pacific Coastline (IFR/LIFR obs have been
observed at times along the coast, and will lift to MVFR later this
morning). Showers will move inland across the terminals through the
day. A small portion of the far northeast Cascades a 20% chance of
thunder this afternoon. Post-front, expect a convergence zone to
keep showers lingering in Snohomish County through tonight, with a
few more scattered showers lingering along the coast for Thursday.
MVFR becomes increasingly probable Thursday morning for most.
Southwest/west winds will continue through the TAF period at 5-10
kt, with a few occasional gusts 15-20 kt for portions of Puget
Sound, North Interior & Strait of Juan de Fuca areas.
KSEA...VFR today (lowering ceilings), then MVFR likely after 09Z
Thursday morning as shower activity winds down later tonight.
Convergence zone activity at this time is expected to remain north
of the terminal. Southwest winds 5-10 kt with a few gusts to 20 kt
at times.
HPR
&&
.MARINE...
High pressure is moving inland this morning, with a cold front on
track to move through the waters this morning/early afternoon.
Shower activity will progress over the waters with little to no
visual impacts expected with the rain rates. The main concern
remains diurnal pushes in the Strait of Juan de Fuca. Small craft
conditions remain expected today, and continuing into Thursday. Gale
probability remains very low with this system. Another system passes
over the waters Friday through Saturday, with a 20% chance of
thunder with the shower activity. Probability of impacts with this
system remain low at this time. Seas remain under 10 ft at all times
in the forecast, with ranges of 4-6 ft or 6-8 ft.
HPR
&&
.FIRE WEATHER...
The transition to onshore flow overnight has brought higher
relative humidities to the area. This will alleviate fire
weather conditions across Western Washington. The cool and
unsettled pattern into the first part of next week will keep
fire weather concerns at a minimum. Felton
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...None.
PZ...Small Craft Advisory until 11 AM PDT Thursday 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