Brier Weather Station
Latitude N 47° 46' 49" Longitude W 122° 16' 48" Elevation 341 ft
205
FXUS66 KSEW 261003
AFDSEW
Area Forecast Discussion
National Weather Service Seattle WA
303 AM PDT Sat Sep 26 2026
.SYNOPSIS...
Weather settling down today with upper level trough to the east,
surface high pressure over the area and split flow aloft
developing off the coast. Little change in the pattern tonight
and Sunday. Flow aloft consolidating off the coast Sunday night
but next system not reaching the area until Tuesday. Much
weaker system most likely will fall apart before it gets to
Western Washington Thursday. Upper level ridge building Friday
with thermally induced surface trough developing along the
Oregon coast.
&&
.SHORT TERM /TODAY THROUGH MONDAY/...
Satellite imagery shows clouds still hanging around over the
Northwest Interior, Cascades and along the coast. Mostly clear
skies elsewhere. With the clearing, temperatures at 3 am/10Z
have dropped into the mid 40s to lower 50s. For the first time
since June 8th the temperature at Seattle-Tacoma airport has
fallen into the 40s ( 49 degrees ).
Dry weekend in store for Western Washington. Upper level trough
east of the area early this morning. Surface high pressure
building today. Split flow aloft developing off the coast today
as well. Little change in the pattern tonight and Sunday.
Patchy fog developing this morning will dissipate before late
morning. A little more fog coverage Sunday morning as the air
mass continues to calm down. Highs today and Sunday even with
some sunshine a little below normal, lower to mid 60s. Lows
tonight in the 40s and lower 50s.
Pattern changes beginning Sunday night with the flow aloft
becoming consolidated off the coast. Next system well to the
northwest, near Haida Gwaii. Mostly clear skies allowing
temperatures to drop into the upper 30s and 40s. The forecast
low of 46 at Seattle-Tacoma airport would be the coldest low
since 45 degrees on May 30th.
Increasing middle and high level clouds Monday as the next
weather system continues to move southeast down the British
Columbia coast. Chance of rain along the north coast by late in
the afternoon. Highs again in the lower to mid 60s. Felton
&&
.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...
Models in good agreement with rain out ahead of the system over
the northern portion of the area Monday night. Slow moving front
dragging through Western Washington Tuesday into Tuesday night.
Not much cool air behind the front with minimal post frontal
shower activity Wednesday.
Inconsistency in the solutions increasing Wednesday night
through Thursday night. Operational runs are dry but enough
ensemble solutions indicating light precipitation to keep
slight chance pops in the forecast. Confidence in this scenario
not very high. Will not be surprised if the pops fall out of the
forecast in the next few runs.
ECMWF has strong upper level ridge building Friday with
thermally induced surface trough developing along the Oregon
coast. GFS has this scenario as well but is 24 hours behind the
ECMWF. For now the general idea is dry and warmer heading into
next weekend. Felton
&&
.AVIATION...
Northwesterly flow aloft this morning and this afternoon as an upper
level ridge builds over the coastal waters. This will turn more
zonal this evening as split flow develops between this low and a
developing trough off the OR waters. Surface winds south to
southwesterly this morning before turning more north to
northeasterly this afternoon. Speeds generally 4-8 kts this morning
before increasing to 8-12 kts this afternoon. Wind speeds expected to
ease tonight back into that initial 4-8 kts range.
Most locations still seeing VFR conditions this early morning
although some isolated MVFR to IFR conditions are present. As winds
continue to ease this morning, cigs expected to lower due to
abundant low-level moisture with widespread MVFR/IFR conditions
expected by 12Z this morning. Cigs expected to lift and return to
VFR in the usual 18-20Z time frame and persist for the remainder of
the TAF period.
KSEA...VFR conditions in place with FEW-SCT clouds around 2000 ft.
With wind speed expected to dip below 5 kts by 12Z, should see cigs
fill in at this level, setting up MVFR conditions for much of the
rest of the morning. VFR breakout still expected around 18Z with
skies clearing throughout the day thanks to building upper level
ridge. Southerly surface winds turning northerly after 18Z with
speeds increasing to 8-12 kts.
18
&&
.MARINE...
Some lingering obs of winds 15-25 kts in remaining areas under
inherited SCA, so will allow headline to run its course until 5 AM
PDT. Winds will continue to ease, falling below any headline
criteria early this morning as direction becomes more offshore with
weak high pressure. On Sunday, an approaching frontal system will
dissipate over the offshore waters. A stronger frontal system will
reach WA Monday night and Tuesday with increasing south winds.
Additional headlines may be needed for this time frame should
forecast remain consistent.
Seas generally 5-7 feet and will continue to ease this morning until
reaching 3-5 ft by noon today. Wave heights rebound this evening
slightly this evening to 4-6 ft before reaching 7-9 ft Sunday and
into Monday. With frontal passage expected Tuesday, seas may rise to
9-11 ft and may need headlines.
18/33
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...None.
PZ...Small Craft Advisory until 5 AM PDT early this morning for
Central U.S. Waters Strait Of Juan De Fuca-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-West Entrance U.S. Waters
Strait Of Juan De Fuca.
&&
$$
NWS SEW Office Area Forecast Discussion