Brier Weather Station
Latitude N 47° 46' 49" Longitude W 122° 16' 48" Elevation 341 ft
087
FXUS66 KSEW 300920
AFDSEW
Area Forecast Discussion
National Weather Service Seattle WA
220 AM PDT Mon Mar 30 2026
.SYNOPSIS...
Surface high pressure plus dry northwesterly flow aloft giving
Western Washington a sunny day today. The flow aloft will turn
more westerly tonight with some high clouds moving over the
area. Next system arriving Wednesday with the front moving
through later in the day. Cool upper level low following Thursday.
Weak high pressure building Thursday night will remain over the
area into the weekend.
&&
.SHORT TERM /TODAY THROUGH WEDNESDAY/...
Satellite imagery shows skies have already cleared over the
northern portion of the area with mostly high clouds over the
southern portion. Patchy fog/freezing fog forming over the
Southwest Interior. Convergence zone over King and Pierce
counties last night has dissipated with no precipitation echoes
on the doppler radar. Temperatures at 2 am/09z were in the lower
to mid 30s.
Skies will continue to clear out this morning with a sunny day
in store for Western Washington. Patchy fog over the Southwest
Interior will dissipate later this morning. Even with the
sunshine the air mass aloft is cool so highs only near 50.
Flow aloft turning west southwesterly tonight. This will push
some high clouds into Western Washington. Question is will the
cloud cover be thick enough to prevent temperatures from falling
below freezing. For the most part yes with just the colder
locations like the Southwest Interior dropping just below
freezing. Lows mostly in the 30s.
Another dry day Tuesday with high clouds. The change in the flow
aloft will warm the air mass a bit with highs a few degrees
warmer than today, in the lower to mid 50s.
Next system dropping out of the Gulf of Alaska Tuesday night
already negatively tilted by 12z Wednesday. This will slow down
the eastward movement of the front. With the front well offshore
just chance pops overnight. Lows in the upper 30s to mid 40s.
Front continuing to slow down Wednesday. Front reaching the
coast late in the afternoon. Rain spreading over the area in the
morning continuing through afternoon. Snow levels around 3000
feet with snow in all the passes except maybe Snoqualmie. The
slower arrival of the front will keep new snow amounts in the
Cascades in the 2 to 4 inch range. Higher amounts on Mount
Rainier. Breezy day for the coast and Northwest Interior with
winds increasing in the morning. Highs near 50. Felton
&&
.LONG TERM /WEDNESDAY NIGHT THROUGH SUNDAY/...
Models remaining pretty consistent bringing the front through
Wednesday evening. This is when the heaviest snow will fall in
the Cascades. Low end advisory amounts still possible.
Cool upper level low trailing the front moving through Thursday
keeping showers and low snow levels in the forecast. Weak upper
level ridge building Thursday night. Showers coming to an end.
Weak upper level ridge remaining over the area through Saturday.
Some differences in the models showing up with a weak system
moving by to the north Saturday night into Sunday. The
operational GFS is much stronger with this feature versus the
ECMWF. Ensemble solutions favoring the ECMWF at the moment so
will stay with a dry forecast. Confidence not real high on the
Sunday forecast.
Highs in the lower to mid 50s Thursday warming to the mid 50s to
lower 60s for the weekend. Lows in the mid 30s to lower 40s.
&&
.AVIATION...
Westerly flow continues to prevail across western Washington today.
Skies have become mostly clear across much of the area with some
lingering cirrus over the southern half of the area.
With mostly light winds across the area, this has allowed for low
clouds and fog to begin to develop across the area. OLM and PWT are
already in LIFR, with other area terminals beginning to show fog and
low stratus in the vicinity. Areas of fog and low stratus will
continue to develop across the area this morning.
Conditions will improve from around 17-19Z as winds develop and the
sun burns the fog/clouds away. Afterwards, VFR conditions will
prevail through the remainder of the period with mostly clear skies.
High clouds will begin to fill back in after 06Z Tue.
Light to calm winds will increase to 6 to 12 kt, northerly, late
this morning. Winds peak this afternoon before slowly easing tonight
into early Tuesday.
KSEA...VFR conditions early this morning with scattered low clouds.
Expect low clouds to continue to fill in with low-MVFR to
potentially IFR conditions by 15Z. Limitations in visibility in
patchy fog cannot be ruled out this morning, as well.
Conditions should improve after 18-19Z as winds pick up and the sun
burns off the fog. VFR conditions then prevail through the day with
mostly clear skies. High clouds fill back in after 06Z Tue. N winds
increase to 8-12 kt this afternoon, then slowly easing tonight.
&&
.MARINE...
High pressure will continue to filter in across the area this
morning. Elevated winds will continue early this morning in the
Strait of Georgia and around the northern San Juans early, but those
winds will continue to taper off this morning. Otherwise, light
winds will prevail across the area waters through Tuesday. A low
pressure system will approach the area early Wednesday with
increasing southerly winds. The trend continues with slightly weaker
winds then previously forecast. Small Craft Advisory winds remain
likely (60-90%) across most all the area waters, with only a 15-30%
chance of seeing gale force winds across the coastal waters and the
East Strait of Juan de Fuca. Winds will peak Wednesday afternoon as
the front passes across the waters before decreasing Wednesday
evening as the system tracks away to the southeast. Broad high
pressure will rebuild back across the area Thursday through the end
of the week, keeping winds light.
Seas will remain 3-5 ft through Tuesday. Seas then look to rise up
to 8-10 ft on Wednesday as the system moves through. Seas remain
elevated into Thursday before decreasing once again Friday into the
weekend.
62
&&
.HYDROLOGY...
No river flooding in the next 7 days.
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...None.
PZ...Small Craft Advisory until 5 AM PDT early this morning for
Northern Inland Waters Including The San Juan Islands.
&&
$$
NWS SEW Office Area Forecast Discussion