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459
FXUS66 KSEW 080335
AFDSEW

Area Forecast Discussion
National Weather Service Seattle WA
835 PM PDT Tue May 7 2024

.UPDATE...
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We`re in store for benign conditions here this evening.
Lingering showers are on track to fizzle out as upper-level
ridging builds in. Overnight lows are to fall into the mid 30s to
lower 40s. The previous discussion remains below along with an
updated marine/aviation section.


.SYNOPSIS...An upper level trough will exit the region today and
a ridge of high pressure aloft will begin to build into the area
on Wednesday. The upper ridge will strengthen toward the end of
the week as thermally induced low pressure near the surface
expands northward into the area. Dry conditions will prevail along
with the warmest temperatures of the year thus far on Friday and
Saturday. A weak system passing to the north of the area will
bring a minor cooling trend Sunday into Monday.
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&&

.SHORT TERM /TONIGHT THROUGH SATURDAY/...Scattered showers over much
of the area will linger through the afternoon becoming limited to
the Cascades the evening. There remains a 15-25% chance of
isolated thunder over the Central and South Cascades this evening
before showers completely taper out as upper level ridging begins
to build into the area overnight. Morning clouds Wednesday
morning will give way to sunshine with near normal high
temperatures nosing well into the mid 60s.


The the offshore upper level ridge will tip further over the
region Thursday with thermally induced low pressure expanding
northward along the Oregon coast. This will turn the low level
flow northerly and offshore, which will help warming along the
coastal areas a bit more than the interior. Hoquiam and Forks are
expected to warm into the mid 70s (or higher) on Thursday
afternoon. Interior areas will warm up as well...with lower to mid
70s common from the Seattle area southward. The upper ridge axis
shifts onshore on Friday while the thermal trough remains more or
less oriented along the coast. This will likely be the warmest day
for the coast...with highs reaching the lower to mid 80s
especially along the North Coast...which is daily record
territory. In fact, there is a 90% chance of temperatures at or
above 80 at Forks on Friday. Elsewhere, sunshine and warm
temperatures with similar probabilities for temperatures above 80
across the interior lowlands from the Seattle Metro area southward
, including much of the central Kitsap Peninsula. Model guidance
continues to hint a a more progressive shift in the pattern Friday
night with the ridge axis potentially broadening over much of the
Western US and the thermal trough shifting inland.

.LONG TERM /SATURDAY THROUGH TUESDAY/...The shift of the thermally
induced surface trough onshore will help onshore flow and cooler
temperatures for the Coastal areas with 15 to 20 degrees of
cooling for Saturday. Warm temperatures will very likely linger
for much of the interior, potentially as warm as Friday especially
through the metro area. Onshore flow and a weakening in the ridge
on Sunday as a system passes to the north will help temperatures
dip into the 60s and 70s - still near or just above normal and
dry. Dry and warm spring weather looks to linger into mid week.


&&

.AVIATION...
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Upper-level ridging will continue to build across the
Pacific Northwest through the rest of the week with northwesterly
flow aloft turning northerly through the day Wednesday. Mostly VFR
with a 25-30% chance for MVFR stratus to develop between 14 and 18Z
at the Puget Sound terminals. Otherwise, a return to VFR after 18Z.
Light north to north-northeast winds tonight, variable at times,
then turning northerly 5 to 10 kt Wednesday by 18Z.

KSEA...VFR this evening with light north-northeasterly surface flow
around 5 kt, which should hold through much of the night before
winds transitions more to the north-northwest 8 to 12 kt after 18Z.
MVFR chances have decreased slightly, with a 25% chance through the
14-18Z window. Otherwise, VFR after 18Z.

Davis
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&&

.MARINE...
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Winds have eased across the Strait this evening, thus
ended the Small Craft Advisory for the West Entrance, with wind
gusts still going strong through the central and east Strait.

High pressure will build over the waters through Wednesday night.
Thermally induced low pressure then will move up the coast on
Thursday and shift inland Friday and east of the Cascades later on
Saturday. Westerly winds will continue to remain breezy into
Wednesday, particularly for the central Strait of Juan de Fuca, with
Small Craft Advisory winds during this period, along with adjacent
waters. Northerly winds will increase Wednesday afternoon into
Wednesday evening, especially for the inner Coastal Waters, where
brief SCA wind gusts may be possible. North winds then continue into
the weekend.

Seas of 10 feet will subside to 8 to 9 feet tonight and 6 to 7 feet
on Wednesday.

Davis/JD
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&&

.HYDROLOGY...The daily hydrology discussion has ended until the
start of the next rainy season; it will only be updated as needed.

&&

.SEW WATCHES/WARNINGS/ADVISORIES...
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WA...None.
PZ...Small Craft Advisory until 2 AM PDT Thursday for Central U.S.
     Waters Strait Of Juan De Fuca.

     Small Craft Advisory until 8 AM PDT Wednesday for Admiralty
     Inlet-Coastal Waters From Cape Flattery To James Island 10
     To 60 Nm-Coastal Waters From Cape Flattery To James Island
     Out 10 Nm-Coastal Waters From James Island To Point
     Grenville 10 To 60 Nm-Coastal Waters From James Island To
     Point Grenville Out 10 Nm-Coastal Waters From Point
     Grenville To Cape Shoalwater 10 To 60 Nm-Coastal Waters
     From Point Grenville To Cape Shoalwater Out 10 Nm-East
     Entrance U.S. Waters Strait Of Juan De Fuca.
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&&

$$