180
FXUS62 KCHS 041146
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
746 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/...
A few observation sites have reported light fog this morning.
This should erode quickly over the next hour or so. Otherwise,
forecast was on track and no notable changes were needed.

Independence Day: The mid-levels will consist of a 595 dam High
over the Southeast U.S. in the morning. It`s expected to
gradually weaken into the afternoon, while shifting westward. At
the surface, a stationary front located off our coast at
daybreak will dissipate this morning. During the afternoon,
surface troughing will develop across portions of the Southeast
U.S. Additionally, High pressure will be centered off the Outer
Banks of NC, with it`s periphery stretching into our area. PWATs
will generally be ~1.5", which is a bit below normal for this
time of year. Though, dew points are expected to rise into the
70s closer to the coast. High temperatures should peak in the
mid 90s across most of our area, except cooler at the beaches
due to the afternoon sea breeze. These values are a few degrees
above normal. As a result, heat indices are expected to peak
just short of 105 degrees. Despite the heat and moisture, both
the synoptic models and the CAMs are pointing towards very
little convection today. If any is able to form, it`s most
likely near the Altamaha River this afternoon and early evening,
which is where we have slight chance POPs. The rest of our area
should stay dry. This is due to mid-level dry air and a
temperature inversion around 700 mb. Sun will be mixed with fair
weather cumulus and high clouds.

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 /12Z 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...
SHORT TERM...ETM
LONG TERM...ETM
AVIATION...NED
MARINE...ETM