Brier Weather Station
Latitude N 47° 46' 49" Longitude W 122° 16' 48" Elevation 341 ft
430
FXUS66 KSEW 031010
AFDSEW
Area Forecast Discussion
National Weather Service Seattle WA
310 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/...
Upper level low weatherpersons woe. Satellite imagery shows
upper level low offshore about 200 miles northwest of Hoquiam.
Showers spinning around the low covering most of the area west
of Puget Sound. Temperatures at 3 am/10z were in the 50s.
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. HQM
is the exception where speeds linger in the 10-15 kt range.
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,
however cells of this nature are scattered. This limits the degree
of confidence for TAF inclusion at this time. Lingering moisture
from both precip from yesterday and approaching showers may allow
for a brief drop in cigs early this morning into high-end MVFR as
well. Locations more prone to lower cigs /HQM, OLM, PWT/ could see
cigs fall even lower into brief periods of IFR. By late
morning/early afternoon, widespread VFR conditions are expected to
return thanks to increasing instability. That said, 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, with the exception mentioned above as high-end MVFR
conditions may briefly emerge around 15Z and linger into the late
morning. As per current radar, showers are east of the terminal, but
likely to start entering the area around 13-14Z. After the first
wave passes through, scattered showers will linger in the forecast.
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 SEA falling into
the lower end of expectations. South to southeasterly winds 5-10 kts
turning more southwesterly this afternoon. Speeds generally will
remain consistent.
18
&&
.MARINE...
A Small Craft Advisory continues this morning for the eastern Strait
of Juan de Fuca, Admiralty Inlet, and northern inland waters as
breezy southerly winds persist in these areas. An additional Small
Craft Advisory for the coastal waters will also remain in place
throughout the morning hours, this one for a mix of breezy winds and
heightened seas. Winds and seas will continue to ease together
slowly through the day and into Friday as broad low pressure lingers
over the region. Northerly winds develop Saturday and continue into
early next week.
Showers remain in the forecast today with a 10 to 15% chance of
thunderstorms for all waters Thursday afternoon.
Seas 8 to 10 feet early this morning, steadily falling below SCA
criteria by mid to late morning. Seas further ease to 4 to 6 feet
by tonight and remain there through the weekend.
18
&&
.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