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408
FXUS66 KSEW 080901
AFDSEW

Area Forecast Discussion
National Weather Service Seattle WA
201 AM PDT Wed May 8 2024

.SYNOPSIS...
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A ridge of high pressure aloft will begin to build
into the area today then 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 cooling
trend early next week.
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.SHORT TERM /TODAY THROUGH FRIDAY/...
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Ridging at the surface and
aloft is building into the region today. With plenty of sunshine
today, temperatures will bounce back to near climatological
norms. The upper ridge continues to strengthen on Thursday as low
level northerly flow turns offshore in response to thermally
induced low pressure expanding northward along the coast. High
temperatures will warm several degrees on Thursday...especially
along the coast where offshore flow will boost temps into the mid
70s to near 80. 70s will be common across interior areas from the
Seattle area southward.

The upper ridge weakens slightly on Friday, but 500 millibar
heights remain in the vicinity of 580 dam. Coastal areas are likely
to see another round of warm temperatures before the sea breeze
kicks in late and the thermal trough makes the jump inland.
Friday will be the warmest day thus far this year for much of the
interior lowlands with 70s in the north interior and 80+ from the
Seattle area southward.

.LONG TERM /SATURDAY THROUGH TUESDAY/...A switch to onshore flow
on Saturday will cool coastal areas some 15 to 20 degrees or so
compared to Friday while interior areas remain warm with the
thermal trough in place. Sunday and beyond, the ridge is expected
to flatten as a couple of systems pass by to our north. The main
effect will be to cool temperatures back to near or slightly above
seasonal levels. With the exception of a few possible showers in
the North Cascades, the remainder of the area looks to remain on
the dry side. 27
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.AVIATION...
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Northwest flow aloft will become more northerly today as
an upper level ridge begins to build over the Pacific
Ocean/Northwest through the end of the week. For Wednesday, there`s
a 40% chance of stratus developing this morning (as early as 13Z
through 18Z) over northern Puget Sound terminals. At this time,
models have the most likely scenario of these clouds forming on the
lower-end VFR criteria for CIGs. A smaller chance exists for these
clouds forming at MVFR (20-25%). Once temperatures warm, clouds will
clear for the remainder of the day (with low stratus possible along
the coast late tonight/Thursday morning). Winds will remain light
out of the north at 5 to 10 kt.

KSEA...Morning stratus deck potentially forming in or around the
terminal from 13-18Z Wednesday morning. Will most likely be VFR, but
small chance it comes in as MVFR. Otherwise clear to mostly clear
skies for the remainder of the TAF period. Winds north 6 to 12 kt.

HPR
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.MARINE...
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High pressure will continue to build over the waters
today, with a thermally induced area of low pressure moving up the
coast, and advancing inland Friday. A push of westerly winds through
the central Strait of Juan de Fuca today may become gusty for small
crafts - thus will continue the advisory in place for today. A
couple inner waterways (Puget Sound and Admiralty Inlet) as well as
the coastal waters may see gusty winds out of the north this
afternoon between 15 to 20 kt (chance of winds exceeding this are
extremely low). Remainder of the week will keep winds out of the
north, with potential for breezy winds in the outer coastal waters
this weekend to 15-20 kt.

Seas will fall to 6 to 8 feet today, and remain at this level
through the forecast period.

HPR
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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 this morning 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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$$