550
FXUS62 KCHS 041436
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
1036 AM EDT Thu Jul 4 2024

.SYNOPSIS...
A hot and humid air mass will build over the region late week
into the weekend. A weak cold front could approach the region
by early next week.

&&

.NEAR TERM /THROUGH TONIGHT/...
Visible satellite indicated patches of cirrus clouds drifting
across the forecast area. In addition, a field of cumulus clouds
was expanding across the SC Lowcountry during the late morning
hours. The 12Z observed soundings indicated a strong inversion
centered at H7 with a convective temperature of 92 degrees. The
observed lapse rate between H85-500 was barely over 4 C/km.
Recent runs of the HRRR times a weak sea breeze will push inland
across SE GA and SC during the afternoon. Dewpoints in the wake
of the sea breeze should warm into the mid to upper 70s,
possibly developing some weak instability across the coastal
counties and along the Altamaha River basin. Isolated showers
may occur this afternoon, possibly a lightning strike or two.
High temperatures are forecast to range from the mid 90s inland
to around 90 along the coast.

Tonight: Mid-level High pressure centered over the Lower MS
Valley in the evening will continue to weaken into the
overnight. Surface troughing will persist over portions of the
Southeast U.S., while the periphery of broad High pressure in
the western Atlantic will continue to influence our weather. Dry
conditions are expected to prevail in the evening and overnight.
Expect partly cloudy skies, both low clouds and higher clouds.
Temperatures will generally bottom out in the lower to mid 70s
across most of our area, and the upper 70s along the immediate
coast.

&&

.SHORT TERM /FRIDAY THROUGH SUNDAY/...
Mid level ridge will largely persist over the region late week
into the weekend, although it will become sandwiched between
troughing to the northwest and a closed low over the Atlantic
drifting westward towards the Southeast coast. At the surface,
high pressure will reside offshore while troughing remains
inland. A weak front will approach from the west but should
stall out before making it to the local area.

Friday should see isolated to scattered showers and
thunderstorms in the afternoon and evening. Better coverage is
expected over the weekend with higher moisture and weak upper
support. Activity could trigger off the sea breeze, as well as
the inland trough/front. Rain chances peak 50-60% over inland
areas.

High temperatures are forecast to reach the mid to upper 90s
inland of the immediate coast Friday and Saturday. With elevated
dew points, it will feel even hotter. Heat indices could
approach or even exceed local heat advisory criteria of 108
degrees, especially on Saturday assuming convection holds off
long enough. Sunday should remain below criteria. Highs top out
in the lower 90s with heat indices generally 100-105.

&&

.LONG TERM /SUNDAY NIGHT THROUGH WEDNESDAY/...
Mid level ridge looks to hold over the Southeast coast through
the middle of next week with a broad trough lingering to the
northwest and the aforementioned low over the Atlantic
weakening. A trough of low pressure should persist over inland
areas at the surface. At least scattered showers and
thunderstorms are possible each day, with coverage peaking in
the afternoon and evenings. Temperatures will be near to
slightly above normal.

&&

.AVIATION /14Z THURSDAY THROUGH MONDAY/...
12Z TAFs: Any lingering ground fog is expected to dissipate by
12Z this morning. Ongoing 12Z CHS sounding observed a llvl
inversion with close dewpoint depression. As temperatures warm
this morning, cumulus with MVFR bases are forecast to develop
across the terminals. The low cloud cover may become BKN at
times at KSAV, highlighted with a TEMPO between 13-15Z.
Otherwise, conditions will remain VFR with light ESE winds. No
convection is expected at the TAF sites this Independence Day.

As the case in recent years, following this evening`s
pyrotechnic displays, smoke or haze may result in periods of
visibility restrictions at the terminals tonight. Forecast
soundings indicate that a BL inversion may form as early as 2-3Z
with light and variable winds. Future TAF issuances may include
some degree of visibility restrictions associated with firework
smoke.

Extended Aviation Outlook: Brief flight restrictions are
possible in showers and thunderstorms, mainly in the afternoon
and evenings, through the middle of next week.

&&

.MARINE...
Today and Tonight: NE winds in the morning will clock around to
the ESE in the afternoon with the formation of the sea breeze.
Expect the strongest winds along the land/sea interface in the
afternoon, and across Charleston Harbor. Gusts in these
locations could approach 20 kt. Winds should shift to the S in
the evening, then the SW overnight. Seas will average 2-3 ft.
Little or no convection is forecasted.

Friday through Tuesday: Southerly flow will persist through
early next week. Marine conditions will remain well below small
craft advisory criteria, with speeds 15 knots or less and seas
2-3 feet.

Rip Currents: Today: The combination of a SE swell around 8
seconds, onshore winds this afternoon, and the approaching new
moon will lead to a Moderate Risk of rip currents at all of our
beaches.

Friday: A swell of 2 feet every 10 seconds and proximity to
the new moon will maintain an enhanced risk of rip currents on
Friday. A Moderate risk is forecast at all area beaches.

&&

.CHS WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...None.
MARINE...None.

&&

$$

NEAR TERM...NED
SHORT TERM...ETM
LONG TERM...ETM
AVIATION...NED
MARINE...ETM