688
FXUS62 KCHS 101944
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
344 PM EDT Wed Jul 10 2024

.SYNOPSIS...
A weak front will meander across the area through Saturday.
Atlantic high pressure will then rebuild across the area while
a surface trough exists inland early next week.

&&

.NEAR TERM /UNTIL 6 AM THURSDAY MORNING/...
A cold front will pass across the area tonight, likely coming to
a position just off the coast by daybreak. Aloft, ridging will
persist over the Southeast. Radar late this afternoon was pretty
quiet over the local area. Still could see isolated to perhaps
scattered showers and thunderstorms develop primarily near the
coast, but overall coverage will remain limited. Otherwise,
several observation sites have shown heat indices near or over
108F across Charleston and Berkeley counties this afternoon. A
Heat Advisory remains in effect for these locations.

Any convection that develops will diminish quickly with loss of
heating this evening. The remainder of the night should be dry
over land, with rain chances largely becoming focused over the
coastal waters. Lows will average in the low to mid 70s, with
upper 70s near the immediate coast and in Downtown Charleston.

&&

.SHORT TERM /6 AM THURSDAY MORNING THROUGH SATURDAY/...
Thursday: A weak cold front should stall just off the Georgia coast,
bringing drier air to the region from the northwest in its wake for
a brief period. Aloft, weak ridging will prevail, but show signs of
weakening, while a weak sfc trough/wave advects a moist onshore flow
across coastal South Carolina counties (mainly the Tri-County) late
day and into the overnight period. Convective coverage will
therefore remain more focused across the Tri-County Area, with
isolated to scattered showers/thunderstorms possible mid-late
afternoon into evening hours. Temps will be quite warm, approaching
the mid 90s away from the beaches, but considerable mixing out of
sfc dewpts should limit heat indices to below Heat Advisory
criteria. However, heat indices around 105 are possible across the
Tri-County Area as moisture pools along a seabreeze circulation
before convection/clouds limit the overall concern. Overnight, temps
will remain mild, with lows generally in the mid 70s inland to upper
70s/around 80 near the coast. Additional showers/thunderstorms will
also be possible with a weak sfc trough/wave nearby overnight,
mainly across coastal South Carolina.

Friday and Saturday: Weak low pressure progged across southeast
Georgia will be slow to shift north-northwest this weekend,
eventually pulling a weak sfc front further inland and/or north of
the area late weekend. A moist onshore flow will bring PWATs in
excess of 2 inches across the local area, creating greater chances
of showers/thunderstorms across the region as mid-upper lvl vort
energy drifts north along the Southeast Coast Friday afternoon into
early Saturday. Scattered to potentially numerous showers and
thunderstorms are possible during this time frame, with greatest
coverage occurring during peak heating each afternoon when a
seabreeze interacts with the stalled/slow moving front. There is
even some potential for warm and humid conditions on Saturday that
produce heat indices near 108 degrees across the South Carolina
coastal corridor, but much will depend on convective trends heading
into peak heating hours. Regardless, afternoon highs should range in
the low-mid 90s, warmest across southeast Georgia. Overnight lows
will also remain mild, generally in the mid 70s inland to upper
70s/lower 80s along the beaches.

&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
A weak upper trough will exist over the eastern United States
Saturday night through Monday, then a broad upper ridge will
gradually build across the region from the west heading into the
middle of next week. Convective coverage could be slightly
greater than a typical summertime pattern would display,
especially through Monday as a weak sfc trough lingers. Temps
will gradually climb/warm early next week, with heat indices
peaking near 108 across portions of the local area Monday and
Tuesday afternoons.

&&

.AVIATION /19Z WEDNESDAY THROUGH MONDAY/...
Prevailing VFR through 18z Thursday. Isolated to perhaps
scattered showers and thunderstorms are expected to develop this
afternoon. The chance for direct impact appears too low to
explicitly mention in the TAF at this time. Will amend if
necessary.

Extended Aviation Outlook: Scattered afternoon showers/thunderstorms
could produce tempo flight restrictions at CHS/JZI/SAV terminals
each afternoon, especially during the weekend.

&&

.MARINE...
Tonight: Southwest winds early this evening will veer to the
west and eventually northwest by daybreak as a front moves
into the area. Speeds remain below 15 knots with seas 2-3 feet.

Thursday through Monday: Weak low pressure developing near the
Southeast Coast will be the primary driver in overall wind speed and
direction across local waters this weekend. In general, conditions
are expected to remain well below Small Craft Advisory levels across
local waters with onshore winds around 10-15 kt across SC waters,
but offshore and slightly weaker across GA waters Thursday into
Friday. The pressure gradient should gradually tighten across local
waters during the weekend as low pressure nudges further inland
while a weak wave shifts to the north, but wind speeds should remain
around 15 kt or less. Seas should range between 1-3 ft Thursday,
then gradually build to 2-4 ft during the weekend.

&&

.CHS WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...Heat Advisory until 8 PM EDT this evening for SCZ045-050-052.
MARINE...None.

&&

$$

NEAR TERM...ETM
SHORT TERM...DPB
LONG TERM...JRL
AVIATION...DPB/ETM
MARINE...DPB/ETM