810
FXUS62 KCHS 102256
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
656 PM EDT Thu Jul 10 2025

.SYNOPSIS...
Weak high pressure will extend across the area into early next
week.

&&

.NEAR TERM /UNTIL 6 AM FRIDAY MORNING/...
The region will remain placed between high pressure aloft over the
Gulf of America and a longwave trough extending southward from the
Great Lakes region. A shortwave trough will ripple across the
southern periphery of this longwave trough across the southeastern
states today. This shortwave trough will provide some synoptic
forcing to aid in convection this afternoon.

This Afternoon: An interesting set up today as thunderstorms this
morning across the Charleston Tri-County produced thick cloud cover
that is struggling to erode. Thus, there is a temperature
gradient across the forecast area as of 2 PM, with upper 70s to
around 80 across the Charleston Tri-County and Colleton County
in SC, and mid to upper 80s elsewhere. Given the lack of daytime
heating, precipitation chances have diminished across the area
with thick, lingering cloud cover. Elsewhere, the forecast has
changed very little, with showers and thunderstorms possible.
The airmass remains very moist and unstable with SPC
Mesoanalysis showing PWATs 2.0-2.1 inches and upwards of 2500
J/kg of ML CAPE. While CAPE values will be supportive of
convection, SPC Mesoanalysis shows little to no shear to speak
of. Therefore the severe risk remains marginal this afternoon.
Damaging wind gusts will be the main hazard with any strong to
severe storm that is able to form. Hail is also possible, given
a freezing level slightly lower than previous days. Heavy
rainfall is also possible this afternoon, with the HREF showing
a >50% probability of greater than an inch of rainfall across
most of the local area.

Overnight: Convection will gradually wind down through the
night, although a risk for at least isolated showers/tstms will
linger, especially at the coast. Lows will range from the lower
70s well inland to the upper 70s/near 80 at the beaches.

&&

.SHORT TERM /6 AM FRIDAY MORNING THROUGH SUNDAY/...
Aloft, mid-lvl vort energy associated with an h5 shortwave will
slowly traverse the Carolinas this weekend, the bulk of which
interacts with a moderately unstable environment locally on Friday,
before shifting offshore and/or departing to the north this weekend.
Although shear is rather weak on Friday (0-6 km Bulk Shear between
15-20 kt), it should remain sufficient for maintaining thunderstorm
clusters within a moist and moderately unstable environment marked
by PWATs around 2 inches, SBCAPE around 1500-2000 J/kg, mid-lvl
lapse rates between -7.5 to -8.5 C/km and modest DCAPE, suggesting
the potential for a few stronger thunderstorms and/or perhaps a
marginally severe thunderstorm Friday afternoon/evening. By
Saturday, shear and mid-lvl forcing become weaker, suggesting
slightly less precip coverage and more "general" type thunderstorms
during peak diurnal heating hours as the pattern becomes more
typical of summertime. However, a stronger thunderstorm can not be
ruled out with ample moisture and heating in place, perhaps near an
inland moving sea breeze. Afternoon highs should remain in the low-
mid 90s, while overnight lows are mild, only dipping into the low-
mid 70s inland to upper 70s/around 80 near the beaches and across
Downtown Charleston.

On Sunday, convective activity resembles a summertime pattern with
scattered afternoon/evening showers and thunderstorms that mostly
remain sub-severe, but with a limited potential to become strong.
The main issue will be warmer temps as the large-scale ridging
expands across the Southeast United States. Afternoon highs should
approach the mid 90s away from the beaches, and when combined with
sfc dewpts in the low-mid 70s, support heat index values around 105
degrees. A downslope wind should help mix out dewpts sufficiently to
keep heat index values just below Heat Advisory levels, but a few
spots could touch 108 degrees during peak heating hours.

&&

.LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/...
Ridging will continue to build over the Deep South early next week,
while an upper level low could develop across the Caribbean and move
toward the Southeast Coast by the middle of next week. Typical
diurnal convection will continue Monday with scattered showers and
thunderstorms forecast, before an increase in precip coverage is
possible by the middle of next week as the mid-upper lvl disturbance
arrives. Monday will display above normal temps with highs largely
in the mid-upper 90s. These temps along with sfc dewpts in the mid
70s could support marginal Heat Advisory conditions during peak
heating hours Monday afternoon. Thereafter, precip coverage could
play a role in maintaining heat index values below Heat Advisory
conditions mid week.

&&

.AVIATION /00Z FRIDAY THROUGH TUESDAY/...
KCHS/KJZI/KSAV: The bulk of the thunderstorm activity has moved
offshore as of 00Z, with lingering stratiform rain impacting all
three terminals through the next few hours. Instability remains
plentiful across southeastern GA so TSRA has been maintained at
KSAV through 02Z, with -RA at KCHS and KJZI. Rainfall will taper
off after 02Z with prevailing VFR prevailing through the
remainder of the 00Z TAF period. Afternoon showers and
thunderstorms will be possible again tomorrow, however the
timing of any impacts is uncertain and confidence is low.
Therefore only VCTS has been included near the end of the 00Z
TAF period.

Extended Aviation Outlook: Periods of flight restrictions are likely
at CHS/JZI/SAV terminals Friday afternoon/evening due to shower and
thunderstorm activity. Precip coverage becomes more typical of a
summertime pattern late weekend and into early next week, with TEMPO
flight restrictions possible due to shower/thunderstorm activity
each day at all terminals.

&&

.MARINE...
Through Tonight: A S to SW flow will prevail through tonight as
surface high pressure holds strong offshore. Winds will
generally remain 15 kt or less, but some gusts to 20 kt are
possible near the land/sea interface and Charleston Harbor this
afternoon as the sea breeze moves inland. Seas will average 2-3
ft. Clusters of strong to severe tstms may move offshore this
evening and pose a risk for wind gusts in excess of 34 kt,
frequent cloud- to- ground lightning and vsbys less than 1 NM in
locally heavy rainfall. Special Marine Warnings may be needed.

Friday through Tuesday: Weak mid-lvl energy departing the region
early weekend could result in scattered shower/thunderstorm activity
across local waters, and perhaps a strong and/or isolated severe
thunderstorm. Outside convection, a typical summertime pattern will
return late weekend and persist into early next week with Atlantic
high pressure centered offshore and weak sfc troughing developing
inland each day. This should result in relatively benign conditions
across local waters, with south to southwest winds around 15 kt or
less each day and seas between 2-4 ft early weekend, subsiding to 1-
3 ft heading into next week. A few gusts up to 20 kt are possible,
highest along the coast and in the Charleston Harbor due to sea
breeze influences each afternoon.

&&

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

&&

$$

NEAR TERM...CPM
SHORT TERM...DPB
LONG TERM...DPB
AVIATION...CPM/DPB
MARINE...CPM/DPB