522
FXUS66 KSEW 252145
AFDSEW

Area Forecast Discussion
National Weather Service Seattle WA
245 PM PDT Sat May 25 2024

.SYNOPSIS...Showery and cooler conditions will continue into
Sunday as an upper level trough moves through the region. Upper
level ridging will slowly begin to build east of our area through
Monday for slightly warmer temps, with troughing over the Pacific
still keeping an influence over western Washington. A frontal
system will move through on Tuesday for another bout of rain and
cooler temperatures.

&&

.SHORT TERM /TONIGHT THROUGH TUESDAY/...Recent radar imagery shows
scattered showers throughout most of the interior areas, with a
weak convergence zone around the Snohomish/King county line. This
is mainly due to onshore flow from a upper level trough moving
through western Washington this afternoon. Convergence zone will
start to dissipate this evening along with scattered rain showers
throughout the interior. QPF looks meager, so most locations will
likely remain dry heading into tonight. High temps this afternoon
look to remain in the mid to upper 50s.

A weak frontal system will eject from a large upper level trough
in the Gulf of Alaska and move through the northern part of our
area on Sunday. This system will brush through the northern
portion of our area, with the main area of precip being centered
along the north coast, the Cascades, and the Northwest Interior.
There may be a stray shower or two in the interior lowlands, but
most likely will remain dry into Monday. High temps will remain in
the mid to upper 50s.

An upper level ridge will star to build east of our area, in the
Interior West.. while broad troughing offshore will remain close
enough to keep an influence over western Washington. Temperatures
will also warm up a little on Memorial Day, with high temps in the
upper 60s in the interior lowlands, while locations near the water
will be in the lower 60s. Shower chances increase through the
evening and into Tuesday morning as a frontal system approaches
the area while the upper trough digs southward. Showers will
start to push in through the interior Tuesday afternoon and
largely continue into Wednesday.

.LONG TERM /WEDNESDAY THROUGH SATURDAY/...Extended ensemble
guidance agrees on upper level troughing continuing through
late Wednesday, with showers decreasing in coverage on Thursday.
Cluster guidance are in agreement on an upper level ridge
building offshore western Washington into the weekend, providing
drier and warmer conditions.

Mazurkiewicz

&&

.AVIATION...Onshore flow will ease this evening with showers
diminishing. Rain will spread inland on Sunday as a warm front
moves in and most areas will see MVFR conditions. The front will
lift north into southern B.C. Sunday afternoon and evening (with
showers mainly over the North Coast and North Cascades). 33

KSEA...VFR this evening with gusty S/SW winds to 25-30kt, easing
to 15-20kt after 06z. MVFR conditions return by 09-12z with light
rain in the vicinity through 18z. 33

&&

.MARINE...Onshore flow will ease tonight with strongest winds
through the Strait of Juan de Fuca. A warm front will brush the
area on Sunday then lift north into southern B.C. Sunday afternoon
and evening. Another frontal system will cross western Washington
on Tuesday, followed by onshore flow Tuesday night and Wednesday.
33

&&

.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.

&&

$$