744
FXUS66 KSEW 260951
AFDSEW

Area Forecast Discussion
National Weather Service Seattle WA
251 AM PDT Wed Jun 26 2024

.SYNOPSIS...A shift in the pattern will bring the next upper
trough to the Pacific Northwest, bringing cooler temperatures,
breezy winds, and the return of precipitation today and Thursday.
The cycle then repeats with dry and warmer conditions Friday ahead
of the next disturbance that reaches the area over the weekend.

&&

.SHORT TERM /TODAY THROUGH FRIDAY/...A pattern change brings
cooler and wetter weather back to western WA as an upper level low
moves through the Pac NW. For today, showers will be mostly
concentrated along the coast and in the mountains with just
isolated to scattered coverage in the interior. The air mass is
most unstable along the Cascade crest and there is a chance of
thunderstorms too, especially in the North Cascades. We`re in
post-frontal onshore flow tonight with ongoing showers and a
convergence zone over the north sound. Winds will be gusty in the
central interior and south sound in the 20-30 MPH range. With the
cooler air mass in place, temps will drop a few degrees cooler
than average with highs in the 60s along the coast and near 70 in
the interior.

Onshore flow continues into Thursday as the upper low shifts
slowly E/NE toward southern Alberta. For western WA, plenty more
showers, especially over the coast and mountains, as the low
level air mass remains moist. Convergence zone showers will
continue too, focused along the King/Snohomish line. Temperatures
will continue to trend below average with highs in the 60s.

High pressure rebuilds over the region on Friday as the upper low
departs. Look for drier weather with near average temps. 33

.LONG TERM /SATURDAY THROUGH TUESDAY/...Blocking high pressure,
centered over the Rockies, keeps systems offshore as we move into
Saturday. Wetter weather returns again Saturday night and Sunday
as the ridge shifts east and a trough rotates through western WA.
Weak high pressure nudges inland early next week with a few light
showers mainly over the coast and mountains. 33

&&

.AVIATION...South-southwesterly flow aloft this morning as an
upper level trough approaches W WA along with a associated cold
front. Mid and high level clouds continue to stream in ahead of
the aforementioned front, with VFR conditions in place at all
terminals early this morning. Ceilings will start to gradually
lower through the afternoon and evening as the front crosses over
the area, with rain firstly moving into coastal locations later
this morning with MVFR/IFR ceilings. Ceilings will begin to lower
through interior terminals after 00z, with most guidance hinting
at mostly MVFR conditions, with a few localized pockets of IFR at
lower prone locations. These lower ceilings will likely stay
through the evening and into most of the overnight hours as
showers persist throughout the area.

N/NW winds this morning will turn to the S/SW and increase to
around 12 to 17 knots, with gusts up to 20 to 25 knots possible
throughout the afternoon. Winds will start to gradually ease up
to 8 to 12 knots around 04z-06z.

KSEA...VFR conditions early this morning will continue through the
first part of the day. N/NW winds around 4 to 8 knots this
morning will transition to S/SW and begin increasing after 15z to
around 12 to 16 knots, with gusts around 20 to 25 knots at times
through the afternoon. Rain showers will start to move through the
terminal 04z-06z with ceilings lowering to MVFR through the
overnight period.

Maz

&&

.MARINE...A frontal system will move through the area waters this
morning and into the afternoon, with breezy south-southwesterly
winds throughout the interior waters. Guidance still shows small
craft advisory strength westerlies through the Strait of Juan De
Fuca this morning through the afternoon, maintaining around 20 to
30 kts. Southerlies will also increase throughout the Puget Sound
waters this afternoon (15 to 25 kts) before gradually decreasing
into the evening as the front passes through.

Weak high pressure looks to build offshore briefly throughout the
end of the week, with diurnal pushes down the Strait likely at
times. Additional systems look to push through the area waters
through the weekend and into the first part of next week.

Coastal seas 3 to 5 feet this morning will generally maintain
through Friday, before increasing to 4 to 6 feet over the weekend.

Maz

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...None.
PZ...Small Craft Advisory until 11 PM PDT this evening for Central
     U.S. Waters Strait Of Juan De Fuca-East Entrance U.S.
     Waters Strait Of Juan De Fuca.

     Small Craft Advisory from 8 AM this morning to 9 PM PDT this
     evening for Admiralty Inlet-Puget Sound and Hood Canal.

&&

$$