Brier Weather Station
Latitude N 47° 46' 49" Longitude W 122° 16' 48" Elevation 341 ft
502
FXUS66 KSEW 031633
AFDSEW
Area Forecast Discussion
National Weather Service Seattle WA
933 AM PDT Fri Jul 3 2026
.SYNOPSIS...Weak upper level trough remaining over the area
through Saturday. Upper level ridge building Sunday with Western
Washington on the backside of the ridge Monday and Tuesday. Weak
system moving through Wednesday with an upper level trough
over the area Thursday.
&&
.SHORT TERM /TODAY THROUGH SUNDAY/...No significant change made
to the forecast this morning. The previous discussion can be
found below:
Not much left of the front but still a chance of showers for
the Northwest Interior this morning. Elsewhere low level flow
fairly light keeping skies cloudy through the morning hours. No
upper level ridging to provide some subsidence to get rid of the
low level moisture. Will have to rely on the near solstice
sunshine. This should at least bring about partly sunny skies
this afternoon. Highs still below normal, in the mid 60s to mid
70s.
Little change in the pattern tonight and Saturday with a weak
upper level trough still over the area. Low level onshore flow
will reestablish the marine layer over the interior overnight
with skies once again cloudy by sunrise. Like today the early
July sun will work on the marine layer with the layer thinning
out enough for some sunshine in the afternoon. Lows in the
upper 40s to mid 50s. Highs in the mid 60s to mid 70s.
Large upper level ridge centered over the four corners region
will begin to build northwest Saturday night into Sunday. 500 mb
heights rising into the lower 580 dms by 00z Monday. Low level
flow remaining onshore but turns northwesterly Saturday night.
This will weaken the marine layer over the area resulting in
more sunshine Sunday. The onshore flow will put a cap on the
daytime highs. Most places in the interior getting into the
70s. Highs on the coast in the mid to upper 60s. Lows Sunday
morning mid 40s to mid 50s.
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
Main story in the extended period is the lack of a good upper
level ridge over Western Washington through next week. Some
ridging Sunday night into Monday but the ridge axis is well to
the east. Low level flow remaining onshore. Flow aloft turning
southwesterly as an upper level trough digs offshore between
130W and 140W. Monday looks to be the warmest day of the
forecast period with highs in the mid 70s to mid 80s over the
interior and mid to upper 60s on the coast.
Upper level ridge moving east Tuesday with 500 mb heights
beginning to fall over Western Washington. Low level onshore
flow picking up a touch resulting in a slightly cooler day with
highs back into the 70s for the interior and mid 60s on the
coast.
Weak front moving into the area Wednesday for a chance of rain
along the coast, and over the Olympics and North Cascades.
Cooler with more cloud cover. Highs in the mid 60s to lower 70s
for the interior and lower 60s for the coast.
Weak upper level troughiness hanging around behind the system
Thursday with post frontal onshore flow. Models might be giving
climatology a little too much credit with highs in the 70s over
the interior and mid 60s on the coast. Will not be surprised if
we end up a little cooler than the current forecast.
&&
.AVIATION...
A mix of MVFR/IFR cigs this morning with lowered visibility in light
showers/drizzle. Shower activity expected to diminish by the
afternoon. Improvement for the interior terminals expected this
afternoon after 19-22z. Another round of MVFR cigs possible
tonight, with latest probabilities around 40-70%. It is unlikely
any improvement will be seen along the coast and Strait of Juan
de Fuca. Calm to light SW winds early this morning will
increase to 5-8 kt this afternoon. WNW winds this evening at PAE
will drift south to BFI/SEA this evening by 01/02z. Winds
return back to SW to BFI/SEA after 08z/09z.
KSEA...VFR/MVFR this morning. Ceilings rebound in the afternoon
to VFR after 21. MVFR cigs return after 10z, with latest
probabilities around 40-50%. SW winds through the afternoon
around 5-7 kt will shift WNW after by 02z. Winds then transition
back to SW after 09z.
29/Mazurkiewicz
&&
.MARINE...
Broad high pressure over the northeast Pacific with lower pressure
inland will maintain onshore flow for the majority of the forecast
period. This will result in diurnally driven westerlies through the
Strait of Juan de Fuca that may reach advisory level. Today`s
westerlies are expected to reach advisory thresholds. Stronger
westerlies expected on Saturday, with a 70-90% chance of winds
exceeding 21 kt. Another weak front will move over the waters late
Friday/early Saturday. High pressure is expected to rebuild over the
waters behind the front this weekend into early next week. High
pressure will weaken on Tuesday as another frontal system moves over
the waters.
Seas remain 5 feet or lower through mid Saturday and will build to 8-
10 feet by Sunday. Seas will subside below 10 feet on Monday.
29
&&
.FIRE WEATHER...
Even with the slight warming trend into next Monday the low
level onshore pattern will remain intact. This will keep good overnight
relative humidity recoveries in the forecast and help subdue fire
weather concerns despite the warmer temperatures. Another front
in the middle of next week will bring a chance of showers to
portions of the mountains and the coast keeping fire weather
concerns at a minimum. Felton
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...None.
PZ...Small Craft Advisory from 5 PM this afternoon to 5 AM PDT
Saturday 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