540
FXUS66 KSEW 120940
AFDSEW

Area Forecast Discussion
National Weather Service Seattle WA
240 AM PDT Thu Jun 12 2025

.SYNOPSIS...A weak upper trough will move into Western Washington
today then remain over the area on Friday. This will lead to
cooler temperatures, increased cloud cover, and occasional chances
for mountain showers and coastal drizzle. Upper ridging will
weakly rebuild late in the weekend for a modest warming trend
before another trough approaches the area early in the coming
week.

&&

.SHORT TERM /TODAY THROUGH SATURDAY/...A weak upper trough will
move into Western Washington late today for a mostly cloudy day
ahead and temperatures a little below average. The trough will
lead to a chance of showers across the North Cascades and near the
Canadian border tonight and Friday as a couple of weak disturbances
pivot across the region. Otherwise, mainly dry conditions are
expected.

An upper level trough will start to dig southward offshore on
Saturday. This will lead to a slight rise in heights over Western
Washington. Interior high temperatures will edge closer to
normal, but continuing onshore flow will ensure that coastal areas
will remain mostly cloudy and on the cool side.

.LONG TERM /SUNDAY THROUGH WEDNESDAY/...The pattern remains rather
static heading into Sunday with an upper trough offshore and weak
ridging over Western Washington. Model agreement is starting to
fall into place early next week more so than the past few nights.
A weak upper trough is slated to move onshore on Monday, but will
probably produce little more than a bump in onshore flow and the
associated slight cooling that comes with it. A majority of the ensembles
from both the GFS and Euro are now targeting the Tuesday/Wednesday
period for a somewhat more substantial upper trough (by mid June
standards) to move into the region and produce some light precip.
It`s not shaping up to produce much in the way of impacts, but it
could be the beginning of a more prolonged period of cooler, more
unsettled conditions that will sharply contrast how the month
began. 27

&&

.AVIATION...Upper level trough moving through the area today.
Southwesterly flow aloft becoming westerly behind the trough
tonight. Low level onshore flow through Friday.

MVFR ceilings over parts of the area early this morning. Stratus
will fill in with MVFR ceiling over the entire area by 14z.
Isolated IFR ceilings at the higher airports. Stratus lifting late
morning with the stratus dissipating over the interior 19z-21z.
MVFR ceilings continuing along the coast. Stratus moving back
inland tonight returning to the Puget Sound area 09z-12z.

KSEA...MVFR ceilings through the morning. Stratus dissipating
19-20z. VFR ceilings this afternoon into the early morning hours.
Stratus returning to the terminal around 10z with MVFR ceilings.
Southwest wind 8 to 12 knots becoming west northwesterly 4 to 8
knots around 01z. Winds becoming southwesterly again around 06z.
Felton

&&

.MARINE...Surface high pressure centered offshore through the end
of the week will move closer to the coastal waters over the
weekend. A weakening front will reach the waters Monday night.

Small craft advisory westerly winds lingering in the Central and
Eastern Strait of Juan de Fuca this morning. Winds easing late
morning then increasing again this evening back up to small craft
advisory speeds ( 20 to 25 knots ). Diurnal westerly pushes through
Strait of Juan de Fuca are expected through the weekend with
possible small craft advisory winds each evening Friday through
Sunday.

Small craft advisories continue for the outer coastal waters due
to seas remaining generally around 8 feet with dominant periods
around 8 seconds through at least Friday. With the persistent
northwesterly winds, expect seas to remain choppy over the outer
coastal waters through the weekend. Northwesterly winds generally
20 knots or less with the exception of a round of 25 knot winds in
the Northern Outer Waters tonight into Friday morning. Felton

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...None.
PZ...Small Craft Advisory until 9 AM PDT this morning for Central
     U.S. Waters Strait Of Juan De Fuca-East Entrance U.S.
     Waters Strait Of Juan De Fuca.

     Small Craft Advisory from 6 PM this evening to 6 AM PDT Friday
     for Central U.S. Waters Strait Of Juan De Fuca-East
     Entrance U.S. Waters Strait Of Juan De Fuca.

     Small Craft Advisory until 6 PM PDT Friday for Coastal Waters
     From Cape Flattery To James Island 10 To 60 Nm-Coastal
     Waters From James Island To Point Grenville 10 To 60 Nm-
     Coastal Waters From Point Grenville To Cape Shoalwater 10
     To 60 Nm.

&&