Brier Weather Station
Latitude N 47° 46' 49" Longitude W 122° 16' 48" Elevation 341 ft
512
FXUS66 KSEW 311040
AFDSEW
Area Forecast Discussion
National Weather Service Seattle WA
340 AM PDT Fri Jul 31 2026
.SYNOPSIS...
High pressure over the area today will shift east tonight. A
front will move through the area Saturday. Post frontal
convergence zone over mostly Snohomish county Saturday night
will dissipate Sunday morning. Upper level ridge building
offshore Sunday night will move over Western Washington Monday.
The ridge will remain in place through Wednesday. Weak upper
level trough with increasing low level onshore flow towards the
end of next week.
&&
.SHORT TERM /TODAY THROUGH SUNDAY/...
Satellite imagery shows stratus along the north coast with
clear skies over the remainder of the area. Temperatures at 3
AM/10Z were in the 50s and lower 60s.
Today looks to be the warmest day since the 22nd with an upper
level trough offshore pumping up a temporary ridge over Western
Washington. Low level flow doesn`t turn offshore keeping high
temperatures from getting too warm. Highs in the lower to mid
70s on the coast and mid 70s to mid 80s inland.
Upper level ridge moving east tonight with upper level trough
and associated front approaching the coast overnight. Rain
reaching the coast early Saturday morning with a chance of rain
west of Puget Sound and over the Northwest Interior around
sunrise. Increasing clouds will keep lows in a narrow range, mid
and upper 50s.
Upper level through and front moving through Western Washington
Saturday afternoon. Westerly flow aloft will create a bit of a
rain shadow over the Central Puget Sound with the lowest pops
there ( around 30 percent ). Front weakening as it moves inland
so will go with showers as the precipitation type in the
afternoon with rain in the morning. Air mass slightly unstable
with the front producing a small chance of thunderstorms in the
North Cascades. Highs only in the 60s and lower 70s.
Front east of the Cascades Saturday night. Post frontal onshore
flow in the lower levels with a convergence zone developing over
Snohomish County. Pops confined to the convergence zone by late
evening. Lows in the 50s.
Convergence zone dissipating Sunday morning. Low level onshore
flow combined with weak trofiness aloft will keep skies mostly
cloudy and high temperatures below normal, in the mid 60s to
lower 70s. Felton
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
Upper level ridge building offshore Sunday night moving inland
Monday. Ridge remaining over the area at least until Wednesday
with 500 mb heights in the mid 580 dms. Thermally induced
surface trough remaining inland with the low level flow never
turning offshore for any length of time. Highs in the upper 60s
to upper 70s Monday warming to the mid 70s to mid 80s for the
interior by Wednesday. Highs on the coast Tuesday and Wednesday
in the lower to mid 70s.
Upper level ridge moving east Thursday with a weak upper level
trough moving over the area. Low level flow turning weakly
onshore. Highs cooling a little with lower 70s to lower 80s
inland and mid 60s to near 70 along the coast. Felton
&&
.AVIATION...
Southwest flow aloft throughout the period with an upper-trough
offshore in concert with an upper-ridge over the Intermountain West.
Areas of IFR/LIFR stratus is developing along the immediate coast
with patchy stratus across the interior as the morning progress. Any
lingering ceilings should scatter by 16z with VFR areawide
thereafter. Low-stratus looks to redevelop overnight Friday into
Saturday morning as a front enters the region.
KSEA...Mostly clear skies throughout most of the period. Surface
winds W/SW 7 knots or less veering northerly this evening, then
becoming W/NW Friday afternoon. Winds generally ranging between the
W and N between 5-10 kt, becoming more southerly early Saturday
morning ahead of an approaching frontal boundary.
41
&&
.MARINE...Surface high pressure today before a weak front enters the
water tonight into Saturday. A SCA has been issued for the
central/eastern strait for Friday afternoon through early Saturday
morning. An additional SCA may be needed for the same locations
Saturday evening as well once area waters are post-frontal. High
pressure will rebuild over the coastal waters Sunday and remain in
place through Monday. Light flow in the low-levels well into next
week.
41
&&
.FIRE WEATHER...
Elevated fire weather concerns today with above normal
temperatures and afternoon relative humidity values lowering to
near 30 percent over the southern portion of the area as well as
in the foothills.
Front Saturday bringing wetting rain to the north coast and
North Cascades (with a chance of thunderstorms in the North
Cascades). It will be windy with gusts near the crest in the
30-40 MPH range. However, with the wetter and cooler conditions,
min RHs will not reach critical thresholds.
Warmer and drier weather early next week will keep the fire
weather threat elevated, especially next Tuesday and Wednesday,
where min RHs will dip into the 20s and 30s again. Felton/33
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...None.
PZ...Small Craft Advisory from 4 PM this afternoon to 4 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