980
FXUS62 KCHS 292313
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
713 PM EDT Tue Jul 29 2025

.SYNOPSIS...
Atlantic high pressure will prevail for most of the week. A
cold front will stall near the area this weekend.

&&

.NEAR TERM /THROUGH WEDNESDAY/...
Latest SPC mesoanalysis indicated widespread MLCIN across the
forecast area in the wake of widespread thunderstorms earlier
this PM. Rain-cooled temperatures have dropped into the upper
70s to low to mid 80s across the forecast area. Temperatures are
forecast to remain generally steady through the rest of the
evening, then cool to the mid 70s inland to around 80 along the
coast. A few thunderstorms are possible this evening along old
outflow boundaries, but these storms should have short life-
cycles and remain general in strength. It is possible, an
additional strong thunderstorm may develop across far inland GA
during the mid-evening hours.

&&

.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/...
Wednesday: Subtropical ridging will briefly rebuild/consolidate
off the Southeast U.S. coast on Wednesday as a weak surface
trough lingers across the CSRA and the South Carolina Midlands.
Heat and humidity will persist which will support moderate
instability as highs warm into the mid-upper 90s and dewpoints
hold in the 70s. Modified soundings do show some degree of
subsidence near to just under 700 hPa which will likely play
into convection somewhat, but conditions still look to support
scattered to possibly numerous showers/tstms developing mid-late
afternoon. Activity may concentrate across the interior first
where boundaries from convection sparking along the inland
surface trough intersect with the inland moving sea breeze with
mesoscale boundary interactions likely driving how convection
evolves into the evening hours. 29/13z NBM pops of 50-70% inland
with 30-60% closer to the coast look reasonable. With respect
to the heat, heat indices are anticipated to reach the 105-108
range well inland before the onset of convection while values
will peak 108-112 at the coast. A Heat Advisory is in place
11AM-8PM Wednesday for areas roughly along/south of a Metter-
Clyo-Jacksonboro-North Charleston- McClellanville line,
including all of the Savannah Metro Area and parts of the
Charleston Metro Area. Convection will slowly wind down through
the evening hours. Overnight lows will drop into the mid 70s
well inland to the lower 80s at the coast and beaches.

Thursday and Friday: The subtropical ridge aloft will slowly
weaken with time as series of shortwaves passing by well to the
north begin to carve out a longer wave trough across the eastern
CONUS. This will support a continued risk for scattered to
numerous shower/tstms each afternoon/evening. Highs will warm
into the mid-upper 90s both afternoons with lows Friday morning
dropping into the mid 70s inland to the lower 80s at the coast
and beaches. Heat indices should peak 105-108 inland with
108-112 along/east of I-95 both afternoons prior to the onset of
convection. Additional Heat Advisories may be needed, but these
will largely be driven by the timing and extent of afternoon
convection.

&&

.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
The pattern will become quite a bit more active over the
weekend as a cold front stalls over the area as the longwave
trough sharpens across the eastern United States. There remains
some uncertainty on QPF for the weekend (not unexpected given
synoptic models are trying to resolve convective elements so far
out), but conditions look to become much more unsettled across
the region as the front stalls out and interacts with a very
moist (PWATS >2.25") and unstable environment. The potential is
certainly there for several inches of rain to fall Saturday into
Monday with localized storm total amounts for the 3-day period
potentially exceeding 5 inches. There will be a risk for flash
flooding, mainly in the base flash flood category (note the
change in flash flood criteria at WFO Charleston on 1 August),
but is it unclear at this time if the risk for flash flooding
will be widespread enough for a Flood Watch. These are details
that will need to be worked out over the coming days. With the
rain and increased cloud cover comes considerably "cooler"
conditions. Temperatures will fall to well below normal levels
for this time of year, which will feel much more refreshing
after the many days of excessive heat that the area has
experienced.

&&

.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
0Z TAFs: KCLX detected numerous outflow boundaries across the
forecast area this evening. Winds may remain light a variable
through mid evening, then favor south winds between 3 to 5 kts
for the rest of the night. The forecast area has generally been
worked over from widespread thunderstorm activity since this
afternoon. The rest of the night should remain dry and mild.
Restrictive ceilings may develop inland of the terminals late
tonight, the TAFs will remain VFR at this time. HREF indicates
that showers and thunderstorms will likely develop along a wavy
sea breeze Wednesday afternoon. The KCHS will feature a PROB30
between 20-24Z for thunderstorms with a TEMPO at KSAV.

Extended Aviation Forecast: The risk for flight restrictions
due to showers/tstms will persist each afternoon/evening with
chances ramping up over the weekend.

&&

.MARINE...
Rest of Today and Tonight: S to SE winds will veer to the S
this evening as the sea breeze weakens. Overnight winds will
generally be S 5-10 kt. Seas should be 1-2 ft within 20 nm and
2-3 ft for the GA waters beyond 20 nm.

Wednesday through Sunday: Southerly wind regime will prevail
through Friday. Winds will begin to turn northeast over the
weekend as a cold front stalls out near the area. Winds will
generally remain 15 kt or less through the period, although
winds may get as high as 15- 20 kt over the weekend across
mainly the South Carolina waters as the gradient pinches a bit
behind the cold front.

&&

.CLIMATE...
Record High Minimum Temperatures:

July 30:
KCHS: 81/2016
KCXM: 83/2016

July 31:
KCHS: 80/2022
KSAV: 80/2010

August 1:
KCHS: 81/1999
KSAV: 79/2020

&&

.CHS WATCHES/WARNINGS/ADVISORIES...
GA...Heat Advisory from 11 AM to 8 PM EDT Wednesday for GAZ099>101-
     114>119-137>141.
SC...Heat Advisory from 11 AM to 8 PM EDT Wednesday for SCZ047>052.
MARINE...None.

&&

$$

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