644
FXUS66 KSEW 270325
AFDSEW

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

.SYNOPSIS...A passing upper level trough will keep widespread
showers and isolated thunderstorms in the forecast into Thursday.
Warmer and drier conditions set in for Friday into early Saturday,
but another disturbance will bring showers again late Saturday
into Sunday. The pattern remains unsettled, keeping some shower
chances into early next week.


&&

.SHORT TERM /TONIGHT THROUGH SUNDAY/...Shower activity is ongoing
largely east of Puget Sound this evening, with only isolated
showers moving onshore. 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. No major changes have been made this evening and the rest of
the previous discussion will follow.

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 /MONDAY THROUGH THURSDAY/...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 this evening will
transition to more west/northwesterly on Thursday morning as an
upper level low makes its way eastward across Washington. Radar
shows rain showers making their way inland. Thunderstorms remain
possible across portions of the Cascades this evening but the threat
is greatly waning with loss of diurnal heating. 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 evening, 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/McMillian


&&

.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 evening
forecast update. 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.

&&

$$