797
FXUS66 KSEW 271449
AFDSEW

Area Forecast Discussion
National Weather Service Seattle WA
749 AM PDT Thu Jun 27 2024

.SYNOPSIS...Cooler and wetter weather continue today with an upper
low over the region. Warmer and drier conditions set in for
Friday into early Saturday, but another disturbance will bring
showers again late Saturday into Sunday. A few showers linger into
Monday then mainly dry and seasonable weather toward midweek.

&&

.UPDATE...It`s a moody morning across portions of western
Washington as onshore flow has brought light rain and drizzle to
much of the region. The most likely areas for persistent showers
today will be within a Puget Sound Convergence Zone that will
gradually shift south through the day as well as the northern
Cascades. Showers will gradually diminish overnight. The current
forecast handles these trends well and no updates are planned this
morning. -Wolcott-

&&

.SHORT TERM /TODAY THROUGH SATURDAY/...Cool and wet weather
continues across western WA today with an upper level low over the
Pac NW. We`re still under moderate onshore flow today with ongoing
showers, especially over the Cascades. Showers with the
convergence zone will likely shift south and stall over the
King/Snohomish line this morning and afternoon. Temperature-wise,
highs will only track in the 60s today (or around 5 degrees cooler
than average). Showers will gradually taper down overnight as the
upper low departs E/NE toward southern Alberta/Saskatchewan.

Weak high pressure brings drier and slightly warmer weather to the
region on Friday. Temperatures will reach the lower to mid 70s in
the interior and closer to average. The coast will remain in the
60s with NW flow.

The next incoming frontal system will stall offshore on Saturday
while a ridge builds over the Rockies. Western WA is looking
mainly dry through the day with a few light showers coast and
mountains. 33

.LONG TERM /SUNDAY THROUGH WEDNESDAY/...Troughing over the Pac NW
brings a chance of showers on Sunday (coast and mountains) with
isolated shower coverage in the interior. The air mass is slightly
unstable and there`s also a slight chance of thunderstorms in the
North Cascades. Moving forward, broad high pressure over the
eastern Pacific extends through the West and keeps much of the
Pac NW dry. The flow is onshore through early-mid week with
temperatures close to normal. 33

&&

.AVIATION...Flow aloft is westerly/northwesterly as a trough
continues to track through western WA. Continue to show light to
moderate showers, especially in Snohomish County where a convergence
zone is expected to develop throughout the day. Additional showers
will be possible further north in Skagit/Whatcom counties with
remaining wrap around moisture with this low. Widespread MVFR
ceilings will continue through most of today (with possible
improvements to VFR in the Southwest Interior). IFR ceilings will
persist with convergence zone showers in Snohomish County through
the afternoon (form of mist/fog and low CIGs). Southwest winds 8 to
12 kt are expected most areas, with winds potentially becoming
northerly/variable in Puget Sound via the convergence zone from 22Z-
08Z Friday. Widespread MVFR ceilings are expected Friday morning
(with possible IFR in spots).

KSEA...MVFR ceilings will continue with showers/vicinity showers
throughout the day. Southwest winds 8 to 12 kt will diminish this
afternoon (will continue to watch for a possible convergence zone
with wind shifts to the north and east after 22Z this afternoon
through much of this evening).

HPR

&&

.MARINE...A exiting frontal system over the area will lead to
increased onshore flow this afternoon over the area waters, with
small craft westerly winds through the Strait of Juan De Fuca.
Weak high pressure looks to build into the area through Friday,
with additional systems likely into the weekend. Additional
pushes down the Strait are possible through early next week,
although at this time winds look to be below any criteria.

Coastal seas around 4 to 6 feet this morning will continue through
this weekend and into the first half of next week.

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.

&&

$$