330
FXUS62 KCHS 190532
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
132 AM EDT Thu Jun 19 2025

.SYNOPSIS...
High pressure centered in the Atlantic will prevail across the
Southeast. A cold front could approach Friday, possibly passing
just to our north, before high pressure returns through early
next week.

&&

.NEAR TERM /THROUGH TODAY/...
As of 130 AM, KCLX detected a fading cluster of showers over
Colleton County, drifting to the NE. This activity may remain
for an addition hour or two. THe rest of the night should remain
dry. Temperature are on pace to reach near 80 along the coast to
the low 70s inland by daybreak.

&&

.SHORT TERM /TONIGHT THROUGH SATURDAY/...
Thursday and Friday: The base of a mid-level shortwave will slide
toward the region, allowing additional moisture to be advected in
from the west-southwest, bringing PWATs near the 2 inch mark. At the
surface the Atlantic high pressure remains parked to our east-
southeast, while to our west a cold front moves towards the area.
While we may see some diurnally driven and/or sea-breeze driven
convection, additional chances for showers and thunderstorms arrive
as the front approaches during the evening and overnight hours.
While deep-layer shear remains low at around 20 knots, 1500-2000
J/kg of MUCAPE does bring a low-end risk for severe thunderstorms.
Long and skinny CAPE profiles along with DCAPE values of 1000-1500
J/kg would suggest strong wind gusts being the main threat within
storms. The long and skinny CAPE profiles are also indicative of
locally heavy rainfall possible, particularly if any repeat/training
storms occur. SPC has areas along and north of I-16 in a level 1 out
of 5 risk for severe thunderstorms, which matches well with various
AI/ML models that forecast severe thunderstorms.

What happens with the front as it reaches our area remains
uncertain, as some models have it quickly falling apart and/or
becoming stationary, while others bring it through the area
overnight into Friday. As this will be the main driver of our
weather, confidence decreases given the multitude of scenarios that
could play out. Deterministic models and ensembles do point towards
chances for showers and thunderstorms decreasing overnight and into
the morning hours, and increasing again during the afternoon hours
on Friday. Again, depending on the front, 2000 to possibly as much
as 3000 J/kg of MUCAPE may be available, though shear values
continue to remain on the low side. Chances for severe thunderstorms
are uncertain. Temperatures will peak in the lower to mid 90s both
Thursday and Friday, with overnight min temps in the low to mid 70s.

Saturday: A large upper ridge will nudge toward the Southeast U.S.
in the wake of the trough. Surface high pressure will remain fixed
over the Atlantic, while strengthening over the Appalachians.
Diurnal showers and thunderstorms are forecast with chance (30-40%)
POPs in place, as convection is mainly expected to initiate along
the sea breeze. Highs will reach the low 90s to perhaps the mid 90s
inland where convection begins later in the day.

&&

.LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/...
An expansive upper level ridge will build across the Eastern CONUS
as surface high pressure remains over the Atlantic. Diurnally driven
showers and thunderstorms will continue at least through early next
week; however, coverage could be limited to isolated with weak
subsidence in place. Temperatures will remain slightly above normal,
increasing ever so slightly towards the mid 90s in areas away from
the coast. Maximum heat indices will average 100-105F.

&&

.AVIATION /05Z THURSDAY THROUGH MONDAY/...
6Z TAF: This morning, conditions across the terminals should
remain VFR with southwest winds between 5 to 10 kts. A sea
breeze should develop early this afternoon, drifting across the
terminals by mid-afternoon. Isolated to scattered showers and
thunderstorms should develop along the sea breeze. However,
coverage of convection should increase as a H5 trough approaches
from the west late this afternoon into early this evening. The
KCHS and KSAV TAFs will feature TEMPOs from 21-1Z for gusty
winds during TSRA. KJZI should remain east of the convection
for most this afternoon, however, additional development along
outflow boundaries may result in TSRA nearing the terminal
between 20-2Z, highlighted with VCTS.

Extended Aviation Forecast: Brief flight restrictions are possible
in showers and thunderstorms each day, mainly in the afternoon.

&&

.MARINE...
We will remain on the western periphery of Atlantic high
pressure through tonight. A decent afternoon sea breeze will
continue into early evening along the coast including Charleston
Harbor with a few gusts to around 20 kt.

Thursday through Monday: At the surface, Atlantic high pressure
remains parked to our east-southeast, while to our west a cold front
inches closer to the area. This will lead to breezy south southwest
winds gusting near 25 kt and seas building to 4 ft. Although
currently marginal, a Small Craft Advisory could be needed for the
Charleston Harbor and/or the Charleston nearshore waters Thursday
evening. Additionally, showers and thunderstorms are expected to
move offshore in the afternoon into the overnight hours Thursday,
with storms possibly carrying a risk for strong winds. Thereafter,
no marine concerns are expected through the period.

&&

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

&&

$$

NEAR TERM...NED
SHORT TERM...BRS
LONG TERM...BRS
AVIATION...NED
MARINE...BRS/JRL