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906
FXUS66 KSEW 221549
AFDSEW

Area Forecast Discussion
National Weather Service Seattle WA
849 AM PDT Sat Jun 22 2024

.SYNOPSIS...A ridge of high pressure aloft will shift east of the
region today. An upper level trough moving onshore over British
Columbia on Sunday will lead to cloudier and cooler conditions
along with a few showers across mainly northern portions of
Western Washington. A upper level ridge will rebuild into the area
on Monday and Tuesday for drier and warmer conditions. Another
trough arrives in the middle of the coming week for cooler
conditions and additional chances for showers.

&&

.UPDATE...
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Forecast remains largely on track. Will see a few
pockets of blue sky in the cloud cover this morning that will
quickly fill in this afternoon ahead of the weak disturbance
passing through tonight/Sunday. Few showers are also off the
coast, and they will remain primarily over waters and cross over
into Neah Bay/Vicinity today. Precipitation amounts this weekend
are extremely light. One more round of upper 70s to 80 today
before temperatures return to slightly below average next week
with 60s and 70s. Please see the discussion below for more details
(as well as an updated aviation/marine section).

HPR
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&&

.SHORT TERM /TODAY THROUGH MONDAY/...
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Increasing onshore flow
ahead of an approaching upper trough will lead to cooler temps
across the area today. Stratus should remain mostly west of Puget
Sound this morning, but the coast will remain socked in through
the day. Clouds will increase across the interior tonight and a
convergence zone looks likely to develop over Snohomish County for
a few hours on Sunday morning. Cloud cover and spotty precip will
lead to 10 to 15 degrees of cooling Sunday afternoon across much
of the interior lowlands compared to today. The upper trough over
B.C. weakens on Monday with weak upper ridging making some inroads
over Western Washington. This will lead to some clearing by
Monday afternoon with temperatures moderating back to near normal
for late June.

.LONG TERM /TUESDAY THROUGH FRIDAY/...The upper ridge amplifies
as it moves east of the area on Tuesday. This will lead to a dry
and warmer day for interior areas, but increasing onshore flow
will likely to put a lid on temperatures along the coast. Another
upper trough will push onshore Wednesday into early Thursday for
cooler conditions and a decent shot at some showers for much of
Western Washington. There is relatively good model agreement that
weak upper ridging returns by the end of next week for drier
conditions and modestly warmer temperatures. 27
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&&

.AVIATION...
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Upper level ridge to the east combined with upper
level trough offshore giving Western Washington southwesterly flow
aloft through Sunday. Flow aloft will increase tonight into
Sunday. In the lower levels, light onshore flow will increase
tonight.

Areas of lower stratus reside along the coast and portions of the
southern Sound this morning, but expect stratus to retreat back
to the coastline by 18Z. Otherwise, mid to high cloud cover
continues to stream overhead and will persist over the rest of the
area today. Periods of IFR to low end MVFR ceilings will continue
along the coast into Sunday in stratus with VFR generally expected
across the interior this afternoon and evening. Ceilings for the
interior will lower down to 5000 feet likely between 00z-03z and
to MVFR, 2000 to 3000 feet, between 06z-09z. MVFR ceilings
continuing through Sunday morning.

KSEA...Just some mid to high clouds streaming overhead today.
Ceilings will lower down to around 5000 feet around 03Z and to
around 2000 feet 06Z-09Z Sunday. MVFR ceilings continuing through
Sunday morning. Light southwesterly wind increasing to 4 to 8
knots by late morning and to 8 to 12 knots tonight. Felton/14
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&&

.MARINE...
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Weak front moving through the waters today. Onshore
flow increasing behind the front tonight. Weak high pressure over
the coastal waters with lower pressure inland Sunday through
Tuesday. Another system reaching the waters Wednesday.

Westerly winds in the Central and Eastern Strait of Juan de Fuca
will continue to ease this morning, however expect winds to
increase back up to small craft advisory strength for the Central
and Eastern Strait late this afternoon. Small craft advisory
winds continuing into Sunday morning. No advisories or warning for
the remainder of the waters.

Seas around 3 feet today building to 7 feet Sunday into Monday
morning as a larger west wave group arrives. Seas then subside
through the remainder of the forecast period. Felton/14
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&&

.SEW WATCHES/WARNINGS/ADVISORIES...
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WA...None.
PZ...Small Craft Advisory from 2 PM this afternoon to 5 AM PDT Sunday
     for Central U.S. Waters Strait Of Juan De Fuca-East
     Entrance U.S. Waters Strait Of Juan De Fuca.
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&&

$$