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364
FXUS66 KSEW 231559
AFDSEW

Area Forecast Discussion
National Weather Service Seattle WA
859 AM PDT Thu May 23 2024

.SYNOPSIS...Weak high pressure will build in aloft for drier and
somewhat warmer conditions today. Cooler and unsettled conditions
return Friday and will persist into the weekend as another upper
level trough traverses the region. Upper level ridging then looks
to build into the interior West early next week, however troughing
over the northeastern Pacific will continue and will bring additional
chances of precipitation across western Washington at times.

&&

.UPDATE...
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Remains cloudy over much of western Washington this
morning. Some of the low stratus is reaching the roadways,
becoming foggy at Stevens and Snoqualmie Passes, but it remains
elevated elsewhere. An upper level ridge remains on track to clear
out most of the cloud cover this afternoon.

HPR
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&&

.SHORT TERM /TODAY THROUGH SATURDAY/...Weak high pressure will
build in aloft today, bringing drier and slightly warmer conditions
to western Washington. Morning stratus will lift for some afternoon
sun. Afternoon high temperatures will climb a few degrees from
Wednesday and look to top out in the mid to upper 60s across the
interior and upper 50s to low 60s along the coast.

Unsettled conditions return on Friday as an upper level trough
and its associated surface front move into western Washington.
Showers will start to move inland along the coast early Friday and
will gradually move eastward throughout the day, with weak
convergence showers likely developing Friday night into Saturday
across the central Sound. Overall showers will remain rather
light, with QPF generally coming in at a few hundredths to 0.25
inches across the lowlands through Saturday. The mountains will
see some slightly higher amounts, generally between a quarter of
an inch to half an inch of precipitation. High temperatures on
Friday will be in the low to mid 60s across the interior, and mid
50s to low 60s along the coast. Temperatures will cool a few
degrees on Saturday, topping out in the 50s to low 60s.

.LONG TERM /SUNDAY THROUGH WEDNESDAY/...Upper level ridging will
start to build into the interior West later Sunday into Monday,
however western Washington looks to remain under somewhat of a
troughing influence as an upper level trough deepens over the
northeastern Pacific. This will keep precipitation chances in the
forecast Sunday into Monday, mainly for the Olympic Peninsula and
portions of the northern Sound. Uncertainty in the ensembles
increases Tuesday and Wednesday, however ridging over the interior
west looks to push further inland, allowing for the troughing
offshore to nudge into western Washington and for precipitation
potential to increase. Normal to slightly above normal temperatures
are expected Monday into Tuesday, with temperatures cooling a few
degrees on Wednesday. 14

&&

.AVIATION...
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Weak upper level ridging over western WA today
bringing dry weather. The flow aloft is N/NW. The low level air
mass remains moist with MVFR to low-end VFR ceilings. We will see
some scattering with most areas in VFR this afternoon. Rain
spreads inland Friday morning as a weak upper level trough moves
in. 33

KSEA...MVFR conditions this morning then VFR this afternoon. S
winds around 5-8 kt. MVFR conditions return by 12-15z Fri with
rain moving in. 33
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&&

.MARINE...Conditions will continue to trend calmer as high pressure
builds towards the coast, with seas decreasing to 4 to 6 ft by
Thursday afternoon. Building high pressure will cause a westerly
push through the Strait of Juan de Fuca, but winds will stay below
SCA criteria. The next frontal system will cross the waters on
Friday, bringing in a NW swell with waves increasing to 7 to 9 ft
and breezy winds through Saturday. High pressure will allow
conditions to calm towards the end of the weekend and into early
next week.

AL

&&

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

$$