Brier Weather Station
Latitude N 47° 46' 49" Longitude W 122° 16' 48" Elevation 341 ft
007
FXUS66 KSEW 191002
AFDSEW
Area Forecast Discussion
National Weather Service Seattle WA
302 AM PDT Mon Oct 19 2026
.SYNOPSIS...
Upper level low off the coast near 130W will move south ending
up off the Central California coast Tuesday. Southwesterly flow
aloft over the area Wednesday. Front dissipating over Western
Washington Thursday with the trailing upper level trough moving
through Thursday night into Friday. Lots of uncertainty in the
weekend forecast with a few model solutions showing a strong
front moving into the area.
&&
.SHORT TERM /TODAY THROUGH WEDNESDAY/...
Satellite imagery shows high clouds over Western Washington this
morning with an upper level low along 130W west of Hoquiam.
Temperatures at 3 AM/10Z in the 40s and lower 50s.
Upper level low moving south today with southwesterly flow
aloft keeping high clouds over the area. There are some
temperature dew point spreads near 0 early this morning so even
with the cloud cover patchy fog possible until mid morning.
Highs in the upper 50s to mid 60s.
Upper level low continuing to move south tonight and Tuesday
ending up off the Central California coast. As the low moves
farther away high cloud cover will thin out overnight into
Tuesday. Thinner cloud cover overnight plus light surface
gradients will lead to more fog coverage Tuesday morning. The
layer will be shallow enough to dissipate by noon. Lows tonight
mostly in the mid 30s to mid 40s with local lows near freezing
over the Southwest Interior and near the Hood Canal. Highs
Tuesday in the upper 50s to mid 60s.
Upper level low well to the south with a developing upper level
trough well to the north Tuesday night and Wednesday leaving
mostly clear skies over Western Washington. Low level flow
turning offshore but not strong enough to prevent areas of fog
from developing early Wednesday morning. What fog that does form
will dissipate by midday. Lows in the 30s and lower 40s. Highs
in the lower to mid 60s. Felton
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
Extended models in good agreement early on with a weakening
front dissipating over the area Thursday for a chance of showers.
Trailing upper level trough moving through Thursday night into
early Friday with surface high pressure building into the area
for a dry Friday.
Confidence in the forecast for the weekend pretty low at this
point. Model run to run consistency terrible with solutions all
over the place for a developing system off the coast. Previous
run had a few windy solutions for Saturday into Sunday with
rain. Some of the ECMWF ensembles still pointing at a windy
coast and Northwest Interior scenario. GFS solutions much weaker
with the operational run about 20 mb weaker with the surface
low associated with the front versus the ECMWF. With all the
uncertainty weekend forecast a broadbrush chance of rain/rain
likely. Do not have any impactful winds in this forecast
package. Pretty confident the weekend forecast is going to
change a few times before Friday.
Highs in the mid to upper 50s though the period with lows in
the 30s and lower 40s. Felton
&&
.AVIATION...
Southwesterly flow aloft is expected today as an upper trough digs
southward offshore. Flow aloft then turn more variable into early
Tuesday. Mid to high level clouds this morning is limiting areal
coverage of low clouds and fog with the exception of more fog prone
locations in the Southwest Interior, some river valleys, and extreme
southern Puget Sound for the potential of IFR/LIFR conditions.
Impacted terminals expected to improve by 18z for widespread VFR
conditions. Winds will shift more southerly Monday morning then
transition back northerly in the evening. More widespread low
clouds/fog a possibility late tonight into Tuesday morning.
KSEA...Confidence leans toward VFR conditions continuing today. Mid-
high clouds overhead should limit fog development this morning but
can`t rule out fog activity near the vicinity. Surface winds light
this morning. Winds will shift more southerly by the afternoon,
before transitioning northwesterly after 19Z-21Z at 5-8 kt and
remaining into the evening.
41
&&
.MARINE...
A low pressure system passing southward well offshore will keep
winds northerly or weakly offshore for today. Weak high pressure
will remain across the waters into the middle of the week for a
period of benign conditions. A larger swell train near 10-12 feet
generated by active weather well offshore is expected to reach the
coastal waters around Thursday along with an increase in onshore
flow. A front may reach the waters toward the end of the week but
much uncertainly exists in regards to current track and intensity.
41
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...None.
PZ...None.
&&
$$
NWS SEW Office Area Forecast Discussion