890
FXUS66 KSEW 270356
AFDSEW

Area Forecast Discussion
National Weather Service Seattle WA
856 PM PDT Sun May 26 2024

.SYNOPSIS...Cooler and showery conditions will continue across
western Washington today as a frontal system brushes the region.
Upper level ridging will then gradually begin to build east of
the area Monday, allowing for temperatures to warm. Upper level
troughing over the northeastern Pacific will continue to influence
Washington, with the next frontal system poised to move across
the region on Tuesday. Drier and warmer conditions will be
possible late in the week as upper ridging builds offshore.

&&

.SHORT TERM /TONIGHT THROUGH THURSDAY/...Radar imagery shows only
a few stray showers across the region this evening, with
temperatures in the low to mid 50s. Passing showers will continue
tonight as an approaching cold front decays as it arrives. Most
showers will be confined to the Pacific coast, though a few
sprinkles in the higher elevations are possible as well tonight.
Low temperatures in the upper 40s to near 50.

An upper level ridge will start to build east of our region
through Monday, while a large trough will continue to persist just
offshore. Temperatures will warm slightly, reaching closer to
normal, in the upper 60s. Locations near the coast and other
bodies of water will have high temps stay in the mid to upper 50s.
Shower chances will start to increase throughout Monday evening
and into Tuesday as an approaching frontal system and trough
nudges closer to western Washington. The associated frontal system
and trough will spread showers throughout majority of the area
into Tuesday evening, with high temperatures dipping back down to
below average, in the upper 50s.

The aforementioned trough axis will move over western Washington
on Wednesday, allowing for showers to stay around the area. Along
with showers, cooler air aloft might promote some instability that
could lead to a few convective showers over the interior
Wednesday afternoon. If any convective showers do develop, the
primary threats would be lightning and small hail. Although
instability values does not look overly impressive, thunderstorm
chances look to be around 20-25% over region, with MUCAPE values
reaching up to 150-250 J/kg.

.LONG TERM /FRIDAY THROUGH MONDAY/...Showers will decrease in
coverage heading into Thursday as most ensemble guidance agree on
the trough exiting our area and an upper level ridge building
off in the Pacific. Cluster and ensemble based guidance show conditions
beginning to dry our and warm up throughout the end of the week
and into the weekend. Differences lie in the amplitude and
location of the ridge axis, but generally warmer and drier with
highs in the upper 60s to low 70s.

Mazurkiewicz/LH

&&

.AVIATION...Upper level trough digging south well offshore
combined with weak upper level ridge building over Idaho panhandle
giving Western Washington southwest flow aloft through Monday.
Light flow in the lower levels.

Mostly VFR ceilings through Monday. The exception localized MVFR
ceilings near the Puget Sound until 08z and some IFR ceilings
along the coast until 10z.

KSEA...VFR ceilings through Monday. Scattered layer around 2500
feet could go broken briefly until 08z. Southerly wind 4 to 8
knots becoming southwesterly Monday afternoon then northwesterly
00z-03z Tuesday. Felton

&&

.MARINE...A warm front will stall over southern B.C. tonight.
Weak high pressure will shift inland Monday with generally light
winds over the waters. The next Pacific frontal system will move
inland Tuesday, followed by onshore flow Tuesday night and
Wednesday. Small Craft Advisory winds are possible through the
Strait of Juan de Fuca at this time. The flow remains onshore
through the end of the week with strong high pressure over the NE
Pacific. 33/Felton

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
WA...None.
PZ...None.
&&

$$