849
FXUS66 KSEW 262139
AFDSEW

Area Forecast Discussion
National Weather Service Seattle WA
239 PM PDT Wed Jun 26 2024

.SYNOPSIS...An approaching front and passing upper trough will
maintain widespread showers and isolated thunderstorms into
Thursday. Warmer and dry conditions then take hold Friday into
early Saturday in between disturbances, but another weather system
brings more showers late Saturday into Sunday. Some shower chances
remain early next week as the pattern remains somewhat unsettled.

&&

.SHORT TERM /TONIGHT THROUGH SATURDAY/...Radar remains rather
active this afternoon with widespread showers west of Puget Sound
at this hour ahead of the approaching frontal system. Meanwhile
gusty winds continue across the interior with isolated
thunderstorms closer to the Cascades. Expect this activity to
continue through the evening hours as a front and associated low
pressure center move closer to the region. Showers likely continue
through much of Thursday along with abundant cloud cover as the
upper trough shifts eastward through the region. These showers
will be most widespread in the mountains as well as in a
continuing convergence zone.

High pressure returns to the region on Friday in between weather
systems, which should bring increasingly dry conditions as well as
slightly warmer temperatures. This then likely continues into at
least early Saturday before the next disturbance approaches with
additional cloud cover late in the day.

.LONG TERM /SUNDAY THROUGH WEDNESDAY/...The next disturbance in
this series is likely to arrive late Saturday into Sunday, once
again spreading increasing precipitation and cooler conditions
across western Washington. Stronger onshore flow behind the front
may again develop a PSCZ by Sunday evening, and there`s at least
some (10-15%) chance of thunderstorms (especially closer to the
Cascades). Confidence in the forecast decreases toward the middle
of next week with ensemble guidance suggesting perhaps a weak
disturbance or two but otherwise fairly zonal flow early next
week that will maintain temperatures generally near normal and
perhaps some showers at times.     Cullen

&&

.AVIATION...South-southwesterly flow aloft today will transition
to more west/northwesterly on Thursday morning as an upper level
low makes its way eastward across Washington. Radar shows precipitation
continuing to make its way inland along the coast and for areas
generally north of KPAE this afternoon as a frontal system approaches.
Thunderstorms remain possible across portions of the Cascades
this afternoon and evening, with the threat for thunder waning
during the overnight hours. Current conditions at the majority of
the TAF sites are VFR this afternoon, with the exception of KCLM
and KHQM in steadier rain showers. Expect ceilings across the
interior to gradually lower to more widespread MVFR tonight,
likely near 06Z. A few localized pockets of IFR to LIFR will be
possible for terminals in heavier showers. Expect MVFR ceilings
to continue across the region through the overnight hours and
through Thursday morning with showers persisting in the region.
High-res guidance hints the development of a convergence zone
across northern King and Snohomish counties on Thursday, so could
see lower ceilings persist for northern interior terminals through
much of the day.

Winds remain breezy out of the S/SW this afternoon, generally
persisting at around 12-17 knots, with gusts to 20-25 knots at
times. Winds will ease towards 5-10 knots overnight between
04Z-06Z and increase again towards 8-12 knots between 12-15Z
Thursday.

KSEA...VFR conditions with breezy S/SW winds at the terminal.
Gusts around 20 to 25 knots will be possible at times into this
evening before winds ease overnight. S/SW winds increase towards
8-12 knots by mid morning Thursday. Ceilings expected to lower to
MVFR between 04-07Z. Showers will be possible through Thursday
morning. Brief IFR conditions will be possible should any heavier
showers pass over the terminal. 14

&&

.MARINE...An exiting frontal system will keep increased winds in
place over area waters this evening...with speeds in Admiralty
Inlet, Puget Sound and the Central and Eastern Strait maintaining
SCA criteria through 9 PM and 11 PM PDT respectively. That said,
inherited headlines look good and will go unaltered for the
afternoon forecast package. Speeds ease overnight for interior
waters, however northwesterlies over the coastal waters will see
speeds there increase early Thursday morning. This will also result
in a westerly push through the Strait once again, where SCA wind
speeds look to make a return late Thursday afternoon into Thursday
night. Will opt not to hoist a headline for this yet so as to allow
later shifts to gauge run-to-run model consistency. Otherwise, with
weak high pressure in place for the late week period, no other
significant activity is expected. Additional systems look to push
through the area waters through the weekend and into the first part
of next week.

Seas 3 to 5 feet and expected to remain that way through Friday
before increasing to 4 to 6 feet this weekend and into the start of
next week.

18

&&

.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 until 9 PM PDT this evening for Admiralty
     Inlet-Puget Sound and Hood Canal.

&&

$$