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539
FXUS62 KCHS 020736
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
336 AM EDT Thu May 2 2024

.SYNOPSIS...
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Atlantic high pressure will remain across the Southeast through
much of next week.
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&&

.NEAR TERM /THROUGH TONIGHT/...
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This morning: Satellite and observational trends supported the
issuance of a Dense Fog Advisory for all counties through 10 am.
Calm winds, considerable moisture stuck underneath the
subsidence/nocturnal inversion, and very favorable condensation
pressure deficits has prompted this. Not all zones have the
dense fog as of the time of this Area Forecast Discussion, but
based on just about all guidance, the coverage of the dense will
continue to expand.

For today: Strong ridging will prevail aloft, while the local
zones are situated near the western periphery of the Bermuda-
Azores High. Unlike yesterday, the sea breeze boundary is not
expected to be active, given the subsidence aloft and minimal
instability. Even though we lose about 2-3 hours of insolation
due to the morning fog, the ridging aloft and 850 mb
temperatures reaching near 15C will support another warm day.
The low level thickness has done very well the past few days,
but with an east-southeast synoptic flow we didn`t go quite as
high as thew 1000-850 mb thickness implies. Even so, a blend of
the MOS, NBM, and NBM50 was used to produce highs in the mid and
upper 80s away from the beaches. A few places could hit 90F
degrees across interior southeast Georgia.

Tonight: Very little change to the pattern surface and aloft.
Winds will quickly decouple this evening, allowing for good
radiational cooling to occur. Actual lows will be similar to
what they were early this morning. Subsidence aloft and
considerable boundary layer moisture will again lead to fog
developing after midnight. For now we show areas of fog all
counties, but dense fog is likely, and another Dense Fog
Advisory could be required. We included mention in the Hazardous
Weather Outlook.
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&&

.SHORT TERM /FRIDAY THROUGH SUNDAY/...
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Shortwave ridging will persist Friday, though the ridge axis
will move off the coast during the afternoon. Strong mid-level
subsidence is expected to maintain dry conditions over the area,
though we can`t rule out a late day shower or thunderstorm far
inland if something moves in from the west. Highs will be in the
upper 80s except along the coast where prevailing onshore flow
enhanced by an afternoon sea breeze keeps temps in the upper 70s
to lower 80s.

Increasing moisture and a series of shortwaves will move through
Saturday through Sunday. Prevailing onshore flow should produce
a robust sea breeze that will move inland fairly early in the
afternoon both days. Scattered to numerous showers and tstms are
expected, especially farther inland where the sea breeze
interacts with greater instability. Although activity should
wane overnight, the continuation of upper level energy moving
through Saturday night could sustain at least isolated nocturnal
convection. Highs both days will reach the low/mid 80s except
near the coast where a marine layer will reduce temps.
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&&

.LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...
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Monday should again feature scattered diurnal convection given a
weak shortwave moving through, coincident with moderate surface
based instability. A strong subtropical ridge will build over
the area Tuesday through late week, bringing dry weather and
unseasonably warm temperatures. Record high temps are not out of
the question on Wednesday. Highs Wednesday and Thursday are
expected to climb well into the 90s.
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&&

.AVIATION /07Z THURSDAY THROUGH MONDAY/...
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KCHS/KJZI/KSAV: All terminals will experience prevailing flight
restrictions in stratus and fog through mid morning. KCHS and
KJZI will even get down to LIFR and airfield minimums, while
KSAV will at least drop to alternate airfield minimums. VFR
will then prevail after about 1330-1400Z, with SE winds around
10-12 kt in wake of the afternoon sea breeze. But no convection
will occur on that boundary as it moves inland. There will
likely be some fog/stratus again tonight and this will be
handled in later TAF issuances.

Extended Aviation Outlook: Flight restrictions possible in
overnight/early morning fog and stratus. Isolated to scattered
showers and thunderstorms are possible Saturday through Monday.
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&&

.MARINE...
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Today: The local waters will remain near the western side of
Atlantic ridging, resulting in light winds veering around to the
NE this morning, then to the E-SE this afternoon. Even with
local sea breeze enhancements, speeds will be no more than about
10 kt. Seas are just around 2 feet.

The concern will be in regards to fog. There is already quite a
bit fog over land areas of South Carolina and Georgia, and some
of this fog could impact Charleston Harbor, the Port of
Savannah, and the nearshore coastal waters this morning.
Depending upon the coverage of any dense fog, we still might
need to issue a Marine Dense Fog Advisory.

Tonight: The synoptic pattern is basically the same, and E-SE
winds are again no more than about 10 kt, with seas only 2 feet
throughout. As of this time with an onshore flow, fog is likely
not a concern.

Atlantic high pressure will maintain benign conditions over the
marine area Friday through Tuesday. SE winds early in the period
will steadily switch to S and then SW. Wind speeds will
generally be less than 15 kt with seas no higher than 4 ft. The
pattern will favor a good sea breeze each afternoon along the
coast, with winds in Charleston Harbor potentially gusting 15-20
kt at times.
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&&

.CHS WATCHES/WARNINGS/ADVISORIES...
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GA...Dense Fog Advisory until 10 AM EDT this morning for GAZ087-088-
     099>101-114>119-137>141.
SC...Dense Fog Advisory until 10 AM EDT this morning for SCZ040-
     042>045-047>052.
MARINE...None.
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&&

$$

NEAR TERM...
SHORT TERM...JRL
LONG TERM...JRL
AVIATION...
MARINE...