565
FXUS66 KSEW 260329
AFDSEW

Area Forecast Discussion
National Weather Service Seattle WA
829 PM PDT Tue Jun 25 2024

.UPDATE...Dry weather continues this evening with high clouds
along the coast. Clouds will slowly increase tonight into
Wednesday morning. Increasing southerly flow aloft may result in
showers and perhaps an isolated thunderstorm drifting over the
Cascade crest as early as Wednesday morning. Otherwise,
temperatures tonight into the 50s.

&&

.SYNOPSIS...High pressure remains in place with dry and warm
conditions this evening. 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. The
cycle then repeats with dry and warmer conditions Friday ahead of
the next disturbance that reaches the area over the weekend.

&&

.SHORT TERM /TONIGHT THROUGH SATURDAY/...Warm and dry conditions
across the area this afternoon as high pressure remains in placed
over Western Washington. Temperatures are mostly in the 70s for
the interior away from the water, with some pockets of cooler
temperatures closer to the coast.

Nevertheless, a change is in store as a look to the west will
reveal leading clouds ahead of the next disturbance moving closer
to the coastline. We`ll see this next upper trough slide through
the region with an associated cold front sweep through the region.
This will bring widespread cloud cover and showers through the
day. Amounts near the coast and in the mountains may reach between
a quarter of an inch and one half inch. Expect breezy winds to
develop across the region this is front as well, followed by
increasing post-frontal flow that will likely induce at Puget
Sound Convergence zone by Wednesday evening.There is also a
potential for isolated thunderstorms in the Cascades, with the
highest chance in the North Cascades. The trough continues
eastward into Thursday, but with continued onshore low-level flow
expect plenty of lingering clouds and temperatures remaining below
normal. High pressure rebuilds again Friday in between
disturbances for a decrease in clouds and a return closer to
normal temperatures. Some lingering showers in the mountains may
persist, though.

.LONG TERM /SUNDAY THROUGH WEDNESDAY/...The next disturbance clips
the region by late Saturday or Sunday, providing another focus
for precipitation though much less than what is expected
Wednesday. Ensemble guidance in the extended continues to favor a
rather unremarkable pattern with largely zonal flow with some
chances (20-30%) on either side suggesting weak ridging or a few
passing weak troughs through the region. On the whole, expect this
to maintain temperatures generally somewhat close to normal and
at least some showers chances at times for the early portion of
next week.

&&

.AVIATION...An upper level ridge will shift to the east tonight as
an upper level trough approaches the Pacific Northwest. This will
maintain S/SW flow aloft through the TAF period. Satellite this
evening shows mostly clear skies across the interior, with
increasing mid to high level clouds moving over the coast and areas
north of KPAE. Conditions are VFR across the area terminals this
evening and will remain so through the overnight hours. Ceilings
will gradually lower into early Wednesday morning as a surface front
approaches western WA. Expect ceilings to lower towards MVFR on the
coast Wednesday morning as rain starts to move into the region.
Surface winds generally persisting out of the N/NW at around 5-10
knots through tonight, easing overnight. Winds will transition to
the S/SW early Wednesday, most likely between 12-15Z and increase to
10-15 kt. Gusts to 20-25 kt will be possible through the day
Wednesday.

KSEA...VFR conditions will continue through tonight. N/NW surface
winds 7-12 kt will ease during the overnight period and transition
to S/SW between 12-15Z. Winds will increase to 10-15 kt Wednesday
morning, gusting to 20-25kt at times through the afternoon. Light
rain showers looks to make its way into the terminal Wednesday
evening and could briefly bring ceilings down to MVFR at times
under heavier precipitation. 14/McMillian

&&

.MARINE...High pressure will weaken over the coastal waters as a
frontal system approaches the region. The front will move across
the area waters on Wednesday, bringing breezy southerly winds to
the Puget Sound waters. Latest probabilistic guidance shows a
70-90 percent chance of gusts exceeding 22 kt starting late
Wednesday morning. Westerly winds will also increase along the
central and eastern Strait of Juan de Fuca as well on Wednesday,
generally persisting at 20-30 kt. Breezy winds will persist
through the afternoon hours before gradually subsiding in the
evening. High pressure will then briefly build back over the
coastal waters Thursday into Friday before additional frontal
systems move across the area waters over the weekend.

Seas across the coastal waters this afternoon have been hovering
around 3 to 5 feet and will continue to persist within this range
over the next several days, before increasing towards 4-6 feet
again over the weekend. 14

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...None.
PZ...Small Craft Advisory from 5 AM to 11 PM PDT Wednesday 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 to 9 PM PDT Wednesday for
     Admiralty Inlet-Puget Sound and Hood Canal.

&&

$$