Brier Weather Station
Latitude N 47° 46' 49" Longitude W 122° 16' 48" Elevation 341 ft
147
FXUS66 KSEW 021018
AFDSEW
Area Forecast Discussion
National Weather Service Seattle WA
318 AM PDT Tue Jun 2 2026
.SYNOPSIS...
Upper level ridge over the area today with low level offshore
flow. Today could be the warmest day of the year so far. The
ridge will weaken tonight with the low level flow turning
onshore. Upper level trough moving through Wednesday with unsettled
weather continuing into the first part of next week. Cold upper
level low moving into the area Saturday for a chance of
thunderstorms.
&&
.SHORT TERM /TODAY THROUGH THURSDAY/...
Satellite imagery shows band of high clouds from near the San
Juan Islands down to around Goldendale. Mostly clear skies over
the remainder of the area. Wide range of temperatures with mid
40s in the calm wind locations to lower 60s in locations with
some east wind exposure.
Low level flow offshore this morning will weaken this afternoon.
Temperatures aloft are warm but not near record levels. Model
850 mb temperatures this afternoon in the plus 14C-18C range.
This combined with the low level offshore flow will give the
area highs mostly in the 80s. Lower 90s possible in the warmer
locations like the Cascade Foothills and the Southwest
Interior. The Central Coast will be the first to see the
transition to onshore flow this afternoon keeping highs mostly
in the 70s along the beaches. Forecast high of 85 in Seattle
would be the first 85 degree plus day of the year. This is a
little ahead of schedule with the average first 85 degree plus
day June 10th ( earliest April 18, 2016 (89), 1954 and 1957 did
not have an 85 degree plus day ).
Low level flow turning onshore across the entire area this
evening. Upper level trough approaching offshore will lower the
surface pressure enough to prevent gales through the Strait.
High clouds out ahead of the trough moving over Western
Washington overnight keeping lows in the 50s.
Upper level trough moving through Wednesday plus low level
onshore flow giving the area a 15-20 degree cool down with
highs in the 60s and lower 70s under mostly cloudy to cloudy
skies. Trough axis over the Cascades in the afternoon for a
chance of showers and a slight chance of thunderstorms.
Increasing onshore behind the trough Wednesday night will
continue into Thursday. Convergence zone forming over the
Central Puget Sound late Wednesday night/early Thursday morning
for a chance of light showers or drizzle through Thursday
morning. Onshore flow keeping skies at least mostly cloudy
with highs again in the 60s and lower 70s. Lows Thursday morning
in the upper 40s to mid 50s. Felton
&&
.LONG TERM /THURSDAY NIGHT THROUGH MONDAY/...Upper level
trofiness Thursday night through Friday night with low level
onshore flow. Increasing shower chances Friday night. Cool upper
level low moving over the area Saturday. Model 500 mb
temperatures in the -25C to -29C range. Air mass unstable
Saturday especially in the afternoon with lifted indexes in the
0 to -3 range and convective temperatures in the mid to upper
50s. There is even a little CAPE present, 300-500 J/KG. Have a
chance of afternoon thunderstorms for portions of the area. Low
kicks out Saturday night. Another upper level low behind it
currently projected to move inland to the south Monday. Cool
Friday and Saturday with highs in the mid 50s to lower 60s.
Highs trending back towards normal Sunday and Monday, 60s and
lower 70s.
&&
.AVIATION...
An upper level ridge/thermal trough will shift eastward today -
expect the flow aloft to transition to westerly. The flow will turn
more onshore Tuesday into Wednesday as a trough moves inland. For
Wednesday: VFR expected regionwide with a few high clouds overnight,
with light north winds at around 4-8 kt. Tonight/Wednesday: Expect
winds to shift to the south and west early Wednesday morning as the
onshore gradient increases. Mid-level clouds will fill in
regionwide, with a line of lower stratus developing along the coast
(40% for MVFR conditions for coastal terminals, although stratus may
lower offshore). A few showers possible on Wednesday.
KSEA...VFR - clear skies today, then mid clouds filling
overnight/Wednesday. North winds 4-8 kt becoming southwest after 10Z
Wednesday morning at the same speed.
HPR
&&
.MARINE...
A thermal trough under a ridge will begin to shift inland this
afternoon, with offshore flow returning to onshore. A trough/front
will move through on Wednesday, with high pressure building in
behind the trough resulting in stronger onshore gradients. Few
showers will also be possible with this system over the waters. The
winds will pick up Wednesday into Thursday for the eastern two
thirds of the Strait of Juan de Fuca. A small craft advisory was
issued for the first round of winds Wednesday for this area. The
push on Thursday is expected to be the strongest, although recent
ensemble guidance lowered the probability of gale gusts. The pushes
through the remainder of the week are much weaker, and do not have
enough likelihood of producing marine impacts.
Seas will vary from 4-6 to 6-8 ft at times of the week, but again
likely to remain below any impactful levels for small craft.
HPR
&&
.FIRE WEATHER...
Dry and warm today with light offshore flow into the afternoon
hours. High temperatures in the 80s and a few spots touching
90. Winds will be light, but a few easterly gusts 10-15 mph
near the Cascades and over the exposed ridgetops remain
possible. Daytime RHs will bottom out near 20%. Even though
this is a short warm up and fuels have not reached critical
levels lets be careful out there. Onshore flow kicking in
tonight bringing higher humidities Wednesday. Temperatures near
to a little below normal Wednesday into the first part of next
week. Felton
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...None.
PZ...Small Craft Advisory from 2 AM Wednesday to 5 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