Brier Weather Station
Latitude N 47° 46' 49" Longitude W 122° 16' 48" Elevation 341 ft
437
FXUS66 KSEW 270945
AFDSEW
Area Forecast Discussion
National Weather Service Seattle WA
245 AM PDT Fri Mar 27 2026
.SYNOPSIS...
High pressure over Western Washington through Saturday. Weather
system moving down from the northwest moving through late
Sunday. Post frontal showers drying up quickly Monday. Next
system arriving Wednesday.
&&
.SHORT TERM /TODAY THROUGH SUNDAY/...
Satellite imagery shows high clouds near the Canadian border
otherwise mostly clear skies across Western Washington. Fog has
formed along the lower reaches of the Chehalis river.
Temperatures at 2 am/09z were mostly in the 30s.
High pressure over Western Washington today with a front moving
inland well to the north. High clouds at times over the
northern portion with mostly clear skies to the south.
Temperature dew point spreads near zero in some locations so we
could see a little more fog development before sunrise. What fog
does form will only be patchy in coverage and dissipate quickly
after sunrise. High temperatures near normal, lower to mid 50s.
Slight change in the pattern tonight and Saturday as an upper
level trough begins to dig south well offshore. This will turn
the flow aloft southwesterly pushing some more high clouds
towards Western Washington. With the cloud cover lows Saturday
morning a touch warmer than this morning, in the 30s. Highs
Saturday similar to today, in the lower to mid 50s.
Upper level trough continuing to dig and move southeast Saturday
night. By 12z Sunday the trough axis will be near 130W. Still
far enough to the west to keep precipitation chances out of the
forecast. Lows once again in the 30s.
Upper level trough continuing to move southeast with the trough
axis near the coast by 00z Monday. Rain developing along the
coast in the morning spreading inland by late afternoon. Snow
levels below the passes but with the precipitation arriving late
in the day little accumulation. Highs near 50. Felton
&&
.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
Models in good agreement with the trough axis moving through
Sunday night. Steady rain will turn to showers. New snow totals
in the Cascades generally 2 to 4 inches with locally higher
amounts in the North Cascades. Convergence zone developing
behind the trough axis. Northwesterly flow aloft will push the
convergence zone a little further south than its usual location,
over King and Northern Pierce county.
Convergence zone dissipating Monday morning. Shower activity
decreasing with drying northwesterly flow aloft continuing
Monday. Little break in the action Tuesday before the next
system reaches the area Wednesday. System more consolidated the
last couple of runs with pops at least in the likely category
into Wednesday night. Very cool upper level low moving over the
area Thursday keeping showers in the forecast with snow levels
below the passes. Highs near 50 except lower to mid 50s Tuesday.
Lows mostly in the 30s with possible below freezing temperatures
in the colder locations like the Southwest Interior Tuesday
morning.
&&
.AVIATION...
Westerly zonal flow will continue to prevail over western Washington
today. VFR conditions are expected to prevail across the area during
the TAF period as high clouds will persist over the area. The only
exception will be across portions of southwestern Washington this
morning, as light winds and clear skies have allowed areas of patchy
fog to develop. Satellite imagery and traffic cameras show some low
clouds/fog developing along portions of the Chehalis river valley
which will likely push into HQM in the next few hours. OLM will also
have a chance to see a brief period of fog this morning. Winds will
remain northerly through the TAF period, 5 kt or less this morning
increasing to 5-10 kt during the day, then easing again this evening
into early Saturday.
KSEA...VFR conditions through the period with high clouds. North
winds 3-5 kt this morning increasing to 8-10 kt after 18-20Z Fri.
Winds ease once again down to 5 kt or less after 06Z Sat.
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&&
.MARINE...High pressure will be the dominant feature over the next
several days as north to northwesterly winds prevail across the
area. A weak front will pass by to the northwest tonight into early
Saturday and dissipate as it does so. Winds will increase tonight
but likely remain below thresholds (20-40% probability of
exceedance). A weak push down the Strait of Juan de Fuca will ensue
Saturday evening. A disorganized low pressure system will move
across the waters Sunday into early Monday, but stronger high
pressure building behind it could raise winds through the coastal
waters above 20-25 kt early on Monday. A stronger system looks to
move into the region around mid-week, which looks to bring the next
round of gustier winds and building seas to the area waters.
Seas generally remain around 5-8 ft before increasing going into mid-
week.
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&&
.HYDROLOGY...
No river flooding expected in the next 7 days.
&&
.SEW WATCHES/WARNINGS/ADVISORIES...
WA...None.
PZ...None.
&&
$$
NWS SEW Office Area Forecast Discussion