Brier Weather Station
Latitude N 47° 46' 49" Longitude W 122° 16' 48" Elevation 341 ft
055
FXUS66 KSEW 031718
AFDSEW
Area Forecast Discussion
National Weather Service Seattle WA
1018 AM PDT Thu Sep 3 2026
.SYNOPSIS...
Upper level low off the coast today will remain in the vicinity
through Sunday. The low will move east Monday. Weak upper level
trough over the area Tuesday and Wednesday.
&&
.SHORT TERM /TODAY THROUGH SATURDAY/...
The latest forecast this morning remains on track with no
updates. Upper level low offshore today drifting south moving
into Western Oregon Friday morning. Showers rotating around the
low moving through the area at times through this evening. Air
mass somewhat unstable with increasing instability in the
afternoon. Lapse rates at 00z Friday near 7C/km, lifted indexes
between 0 and -3 and convective temperatures in the mid 60s.
Chance of thunderstorms along the coast this morning with a
chance of thunderstorms over the entire area this afternoon.
Thunderstorm and shower chances decreasing quickly this evening
as the air mass stabilizes and the low moves south. Highs today
in the 60s. Lows tonight in the mid 40s to lower 50s.
Upper level low over Oregon Friday wobbles back to the north
over Western Washington Saturday. Shower chances increasing
again Friday night into Saturday especially for the Cascades and
Southwest Washington. Highs Friday in the 60s and Saturday in
the 60s and lower 70s. Lows in the mid 40s to lower 50s. Felton
&&
.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
What is left of the low hanging out west of the Cascades
Saturday night and Sunday keeping a chance of showers in the
forecast mainly over the Cascades. Low kicking out to the east
Monday with a weak upper level trough developing over the area
Tuesday and Wednesday. Little in the way of moisture with the
trough. Low level flow light bringing up the possibility of some
morning fog both days. Highs in the mid 60s to mid 70s. Lows in
the upper 40s and 50s. Felton
&&
.AVIATION...
South to southwest flow aloft for at least the first half of the day
today before shifting more southeasterly to southerly as an an upper
low digs southwards along the Washington coast. Although some
terminals have seen their winds go light and variable, majority are
reporting south to southeasterly with speeds running 5-10 kts.
Widespread VFR conditions this morning although isolated spots of
MVFR can be found along the coast and over the islands. With showers
over the western half of the CWA and slowly moving eastward,
locations under heavier precip could see cigs dip into MVFR
briefly at times, however cells of this nature are scattered.
There is a risk for isolated thunderstorms this afternoon and
early evening, however latest model guidance might be
overestimating potential. Will not rule out development, but
would assign only a 10-20 pct chance of occurring...most
locations leaning toward the lower end of that range while
locations in the SW interior /HQM, OLM/ leaning toward the upper
end. Cigs area-wide likely to lift to mid-cloud levels tonight.
KSEA...VFR conditions are expected to continue for much of the TAF
period. Scattered showers will linger throughout the afternoon.
Given their scattered nature, confidence is shaky regarding any
direct impacts to terminal, and VCSH seems like the best bet
for now. Above thunderstorm discussion applies, with low
confidence of any thunderstorm impacting KSEA. South to
southeasterly winds 5-10 kts turning more southwesterly this
afternoon. Speeds generally will remain consistent.
18/Mazurkiewicz
&&
.MARINE...
Winds are continuing to gradually ease, with the advisories
lingering through 11 AM as gusts are increasingly 20 kt or less. The
additional Small Craft Advisory for the coastal waters will also be
set to expire at 11 AM as seas also subside today. Winds and seas
will continue to ease together slowly through the day and into
Friday as broad low pressure lingers over the region. Showers remain
in the forecast today with a 10 to 15% chance of thunderstorms for
all waters Thursday afternoon, and these showers could produce
lightning and gusty outflow winds.
Northerly winds develop Saturday and continue into early next week.
Seas further ease to 4 to 6 feet by tonight and remain there through
the weekend.
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...None.
PZ...Small Craft Advisory until 11 AM PDT this morning for
Admiralty Inlet-Coastal Waters From Cape Flattery To
James Island 10 To 60 Nm-Coastal Waters From Cape
Flattery To James Island Out 10 Nm-Coastal Waters From
James Island To Point Grenville 10 To 60 Nm-Coastal
Waters From James Island To Point Grenville Out 10 Nm-
Coastal Waters From Point Grenville To Cape Shoalwater 10
To 60 Nm-Coastal Waters From Point Grenville To Cape
Shoalwater Out 10 Nm-East Entrance U.S. Waters Strait Of
Juan De Fuca-Northern Inland Waters Including The San
Juan Islands.
&&
$$
NWS SEW Office Area Forecast Discussion