Brier Weather Station
Latitude N 47° 46' 49" Longitude W 122° 16' 48" Elevation 341 ft
118
FXUS66 KSEW 041029
AFDSEW
Area Forecast Discussion
National Weather Service Seattle WA
329 AM PDT Thu Jun 4 2026
.SYNOPSIS...
Low level onshore flow with southwesterly flow aloft today.
Convergence zone dissipating midday. Upper level low west of
Haida Gwaii this morning will slowly move southeast through
tonight. Upper level disturbance spinning out of the low moving
through Friday. Upper level low moving over Western Washington
Saturday moving east Saturday night. Temporary upper level ridge
Sunday. Another upper low will move through the first part of
next week for more showers and cool temperatures.
&&
.SHORT TERM /TODAY THROUGH SATURDAY/...
Satellite imagery shows cloudy skies over Western Washington
early this morning. Doppler radar has showers over Snohomish and
Northern King County associated with a convergence zone and some
lingering showers over Whatcom county. Temperatures at 3 am/10z
were in the 50s.
Convergence zone remaining in place and continuing through the
morning hours before fizzling midday. Western Washington in
between features today. Southwesterly flow aloft bringing high
cloud cover to the area while low level onshore flow will keep
the lower levels moist at least through the morning hours. Highs
in the 60s and lower 70s.
Upper level low moving slowly south off the British Columbia
coast tonight. Upper level shortwave spinning out of the low
approaching the coast overnight with a chance of showers along
the coast and over the Northwest Interior. Lows in the mid 40s
to lower 50s.
Shortwave moving through Friday in the afternoon keeping at
least a chance of showers in the forecast. Increasing
southwesterly flow aloft will create a rain shadow centered near
Everett in the morning before it fills in the afternoon. Clouds
and showers with highs only near 60.
Upper level low approaching Western Washington Friday night will
move inland Saturday keeping showers in the forecast.
Convective indices lining up for isolated thunderstorms
Saturday. Lifted indexes still in the 0 to -3 range, 500 mb
temperatures -25C to -29C, convective temperatures in the mid
50s and CAPE between 300 and 600 J/KG. Lows in the mid 40s to
lower 50s. Highs like Friday near 60. While both Friday and
Saturday high temperatures are well above record low maximum
temperatures for the day this time of year there is only about a
10 percent chance in Seattle of getting a high in the 50s.
Felton
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
Low weakens to a trough and exits the area Saturday night.
Extended runs showing pretty good run to run consistency with a
temporary upper level ridge moving through Sunday for a brief
break in the showers. Another cool upper level low dropping down
out of the Gulf of Alaska a little slower on the current run
with the low not moving inland over Oregon until Tuesday. Still
the potential for wrap around moisture Wednesday as the low
moves slowly east. At least a chance of showers in the forecast
Monday through Wednesday. Temperatures remain below normal with
highs in the lower to mid 60s. Lows in the mid 40s to lower 50s.
&&
.AVIATION...
Post-front convergence showers continue this morning in portions of
the north sound, Cascades, and North Interior. Flow aloft will
increase from the west. Widespread MVFR is being observed across
most terminals, with localized IFR/LIFR (including low VIS) near the
convergence zone, and VFR conditions in the Northwest Interior.
Models have the low clouds lifting roughly 18-20Z, with VFR
conditions for the remainder of the afternoon and evening. Most
areas will see southwest winds 5-10 kt, with a few gusts to 15-20 kt
in the south sound, and 20-25 kt near the Strait of Juan de Fuca.
Diffluence from winds in the strait will result in north winds from
22Z-06Z before turning back to the southwest. Medium chance again
for MVFR ceilings Friday morning (may be more localized in nature).
Winds also becoming breezy again from the southwest early Friday
morning with gusts to 20 kt in the Puget Sound.
KSEA...MVFR ceilings to continue through roughly 18-20Z. Convergence
zone will remain north of the terminal with showers through the
morning. Lifting/scattering of ceilings to VFR takes place this
afternoon through the evening. Medium chance of MVFR again Friday
morning. Southwest winds in the morning 6-12 kt, will turn north
briefly from 22Z through 06Z, returning to the southwest
tonight/Friday morning. Potential for gusts to 20 kt this morning
and Friday morning.
HPR
&&
.MARINE...
Few showers continue behind a front that pushed through early this
morning across the waters. The showers may reduce visibilities in
isolated portions of the interior waters. Breezy winds with a push
behind the front will continue to produce winds to 25 kt in the
Strait of Juan de Fuca, where a small craft advisory continues
through tonight. A ridge will offshore, making the onshore gradients
relax and decreasing winds. A broad low moves in from the Gulf of
Alaska Friday into the weekend, which will keep the flow onshore.
Pushes through the strait will be much weaker, and at this time will
not produce any impacts to mariners traversing the waters.
Seas remain 6-8 ft or less through the next seven days, but may
approach 9 ft in pockets Monday and Tuesday.
HPR
&&
.FIRE WEATHER...
Low level onshore flow today with temperatures near normal.
Relative humidity values will stay well above critical
thresholds. Cool unsettled weather Friday and Saturday.
Thunderstorm chances elevated Saturday afternoon for the entire
area. Lightning will be a primary hazard, and depending on the
moisture accompanying each thunderstorm, may pose a risk to
drier areas of grasses/cured fuels. Preceding cool conditions
(and live fuels still growing and in the green up phase) will
limit holdover risk as temperatures remain cool early next
week. Felton
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...None.
PZ...Small Craft Advisory until 11 PM PDT this evening 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