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546
FXUS66 KSEW 271553
AFDSEW

Area Forecast Discussion
National Weather Service Seattle WA
853 AM PDT Mon May 27 2024

.SYNOPSIS...An upper level ridge will begin to build to the east
of the area today, while upper level troughing over the northeastern
Pacific continues to influence western Washington. This will
bring warmer temperatures to the area today, but will allow for
some light showers to continue along the coast. The next frontal
system will then move across the region on Tuesday, bringing
greater precipitation chances to the region. Drier and warmer
conditions will be possible late in the week as upper ridging
builds offshore.

&&

.SHORT TERM /TODAY THROUGH WEDNESDAY/...
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No significant change to
the forecast this morning. The previous discussion can be found
below along with an updated aviation discussion:

An upper level ridge will start to build to the east of the area
today, while a trough remains situated over the northeastern
Pacific. This upper trough will continue to influence western
Washington early in the week and will continue to keep showery
conditions along the coast today. Latest radar shows a few light
showers persisting along the coast early this morning. Overall,
expect some light shower activity to continue for areas along the
coast through the morning and afternoon hours, with showers
tapering by late afternoon. High temperatures will warm closer to
seasonal norms and look to top out out in the mid to upper 60s and
upper 50s to low 60s along the coast.

Shower chances then start to increase again late tonight along
the coast as the next frontal system approaches. The front will
then move across the region on Tuesday, allowing for rain to
spread inland Tuesday morning and afternoon. Showers look to taper
heading into Tuesday night, however hi-res guidance does hint at
a convergence zone developing and lingering across the central
Sound Tuesday night into Wednesday. Afternoon high temperatures
will cool back down into the 50s to low 60s for the majority of
the area.

The trough over the northeastern Pacific will then shift its axis
inland on Wednesday, keeping showers in the forecast for the majority
of the area. Cooler air aloft will promote increasing instability
and could generate the development of some convective showers
across the interior by Wednesday afternoon. Lightning, small hail,
gusty winds, and brief heavy downpours will be possible in any
thunderstorms that do develop. Showers will taper late Wednesday
night. High temperatures will be similar to Tuesday, and look to
top out in the 50s to low 60s across the area.

.LONG TERM /THURSDAY THROUGH SUNDAY/...The upper level trough will
continue to push off to the east on Thursday, allowing for upper
level ridging to build over the northeastern Pacific. Ensemble and
deterministic data are in decent agreement that this ridging will
help shape the start of the long term forecast, with a warming
and drying trend commencing over western Washington on Thursday.
Temperatures look to increase a few degrees each day and currently
look to top out in the upper 60s to low 70s by Saturday. The ridge
axis looks to push inland on Saturday, which would open the door
for systems to move back into western Washington by late Saturday
into early Sunday. While discrepancies in the ensemble data remain
in regards to the location of the ridge and trough axis late in
the weekend, have trended with a return to wetter conditions for
now. 14
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&&

.AVIATION...
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A frontal system remains stalled over southern B.C.
today with weak high pressure over Washington. The low level air
mass is moist and there`s pockets of MVFR ceilings in the
interior. Low clouds will scatter by 18z with VFR conditions
expected throughout the rest of the day. Rain increases Tuesday
morning and afternoon as a trough brings the stalled frontal
system inland. 33

KSEA...VFR conditions today. S winds around 5 kt veering to W then
N by 22-02z. Winds turning S again by 12z with rain spreading
inland by 18z Tue (along with MVFR conditions). 33
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&&

.MARINE...Weak high pressure will move across the area waters today
with generally quiet conditions and onshore flow. A weakening cold
front will pass over the region Tuesday with generally sub-advisory
conditions, with the exception being through the central and east
Strait of Juan de Fuca with a 50% chance for advisory-level wind
gusts Tuesday evening. A stronger push through the Strait Wednesday
will likely bring more widespread SCA wind gusts through the Strait.
Onshore flow continues through the second half of the week with
surface high pressure to our southwest. Wave heights look to range
mostly from 4 to 6 feet through much of the week.

Davis

&&

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

$$