680
FXUS66 KSEW 250324
AFDSEW

Area Forecast Discussion
National Weather Service Seattle WA
824 PM PDT Tue Sep 24 2024

.SYNOPSIS...A weather system will move across the region on
Wednesday, bringing more widespread rain, breezy winds, and a
chance of isolated thunderstorms to the area. Another system will
move into the region Thursday night into Friday, before conditions
dry out over the weekend.

&&

.SHORT TERM /TONIGHT THROUGH FRIDAY/...Expect a quiet night
tonight with increasing clouds and lows in the 50s. The previous
discussion can be found below along with updated aviation and
marine sections:

Wednesday brings more fall-like weather as the ridge exits east
and a trough moves inland. Temps will be back in the 60s and
cooler than normal. We may see a little light prefrontal precip
during the morning, then rain increasing through the afternoon as
the main frontal band moves in. The air mass is slightly unstable
over and near the Cascades where isolated thunderstorms are
possible. Showers will shift toward the King/Snohomish line during
the evening with a strong onshore push and setup for a Puget Sound
convergence zone.

We`ll see a brief break on Thursday, then more rain and wind
moving through the region heading into Thursday night and early
Friday. Again, more widespread rainfall amounts for the whole
region with wetting rains in the mountains. Winds will be breezy
overnight Thursday along the North Coast and North Interior with S
gusts to 30-40 MPH. 33

.LONG TERM /SATURDAY THROUGH TUESDAY/...The weekend forecast, for
now, is looking cool but quiet with weak troughing over the
region. Not much moisture or forcing over the region with
generally dry conditions. Highs will reach the lower to mid 60s
with lows in the 40s and 50s. Broad high pressure covers the Pac
NW moving into early next week, keeping the weather mild. Rain
returns Monday night or Tuesday as the ridge pushes east. 33

&&

.AVIATION...Southwest flow aloft will increase into early Wednesday
as a frontal system moves across the area. VFR high clouds for most
areas this evening, with increasing LIFR cigs along the coast and
into the Strait of Juan de Fuca. Cigs will lower tonight into
Wednesday as the frontal system approaches the area. Generally
MVFR/IFR cigs later tonight into Wednesday with LIFR cigs and vsbys
along the coast. Rain will increase later tonight along the coast,
and move into Puget Sound late Wednesday morning into the afternoon.
Vsbys with the rain will likely range 2-5SM. Cigs will slowly lift
towards VFR/MVFR later Wednesday afternoon. A convergence zone is
also expected to develop over Snohomish and King Counties into
Wednesday evening. Light winds this evening will increase from the
S/SW into Wednesday morning, with breezy winds at times into the
afternoon.

KSEA...VFR cigs with high clouds this evening. MVFR stratus expected
to develop generally between 09 to 10z, and continue through
Wednesday. There is also approximately a 50 percent chance of IFR
cigs in the morning, particularly between 11z to 17z. A front will
move across on Wednesday, with rain chances, peaking from 17 to 22z.
A convergence will then develop north of the terminal into Wednesday
evening. Light NW winds this evening will transition S/SW between 06
to 08z, and increase on Wednesday. JD

&&

.MARINE...Surface high pressure will linger over the coastal
waters this evening with northerly/onshore winds and seas over the
coastal waters generally 7 to 9 ft. A relatively strong frontal
system on track to bring backing winds to south-southwest late
tonight into Wednesday followed by northwest winds behind the front.
There is also approximately a 40 to 60 percent chance of a brief
period of SCA wind gusts as the front moves across the Coastal
Waters, mainly between 300 and 900  AM, with brief SCA wind gusts
possible over the northern inland waters Wednesday morning. The
resulting push of westerlies through Strait of Juan de Fuca is then
expected to bring small craft winds, 20 to 30 kt, with around a 20
percent chance of gusts hitting 34 knots or greater. Seas are
expected to come up a bit to 9 to 10 ft with this front as well.

Another, what continues to look stronger, front is expected to
follow on the heels of the first - moving into area waters late
Thursday. This will bring another round of stronger winds with a
higher likelihood of gusty southeasterlies ahead of the front
followed by another strong push through the Strait of Juan de Fuca
during the afternoon and evening hours. Seas are expected to build
further with this system - into the 13 to 16 ft range over the outer
coastal waters Friday.

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...None.
PZ...Small Craft Advisory from noon Wednesday to midnight PDT
     Wednesday night for Central U.S. Waters Strait Of Juan De
     Fuca-East Entrance U.S. Waters Strait Of Juan De Fuca.

&&

$$