588
FXUS62 KCHS 151549
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
1149 AM EDT Sun Jun 15 2025

.SYNOPSIS...
Atlantic high pressure will continue to build across the
Southeast United States through the week.

&&

.NEAR TERM /THROUGH TONIGHT/...
No major changes were made for the noon update. KCLX shows a
few showers trying to get going across interior portions of
Southeast Georgia. Radar trends suggest updrafts are struggling
despite nearly 1500 J/kg of MLCAPE. It seems subsidence is
having an influence for now.

Through This Evening: Morning water vapor imagery shows a
vorticity maximum (vortmax) moving into south central North
Carolina with what appears to be a broad area of subsidence/DNVA
spreading over the Midlands, CSRA and into interior portions of
Southeast South Carolina and Southeast Georgia in its wake. The
latest RAP appears to have sampled this area of DNVA with weak
downward motion noted in model vertical cross sections. The
region of weak subsidence appears to hold well into the
afternoon as the vortmax propagates farther away from South
Carolina which could help curtail convection or at least delay
it a bit as highs warm into the upper 80s/lower 90s.

How much this sinking motion will play into how convection
evolves this afternoon is unclear, but near term high-res
guidance has backed off on the amount of showers/tstms a bit
compared to earlier runs. This may be, at least in part, due to
the aforementioned region of DNVA. Even so, modified soundings
show moderate to locally strong areas of mixed-layer instability
developing this afternoon with dewpoints holding into the 70s.
Convection looks to initiate by early to mid-afternoon across
interior Southeast Georgia within a corridor of higher 850 hPa
theta-e. This activity will then spread and/or develop to the
northeast through the remainder of the afternoon/early evening
along a multitude of convective outflows, possibly concentrating
into the area from Reidsville to Walterboro. The resultant sea
breeze may also come into play late, especially along the I-95
corridor. Convection will slowly wane this evening with the loss
of insolation. Pops were trended down and reoriented slightly
for the mid- morning update to better reflect going short term
convective trends and the expected location of the resultant sea
breeze.

Typical of summer, a few strong to marginally severe tstms could
occur this afternoon and evening. The primary hazards will be
gusty winds, locally heavy rainfall resulting in minor flooding
of low-lying and poor drainage areas, and frequent cloud-to-
ground lightning.

Overnight: Mostly cloudy skies in the evening, becoming partly
cloudy late. Lows in the lower 70s, except mid 70s close to the
coast.

&&

.SHORT TERM /MONDAY THROUGH WEDNESDAY/...
Chances for daily showers and thunderstorms continue into the
week as a surface high pressure over the Atlantic remains off to
our east, and the region remains sandwiched between an upper
level high off to our south-southeast and broad troughing across
the Ohio River Valley. The lack of strong forcing and weak
winds aloft will keep chances for severe weather on the low side
(<5%), while the presence of 1-2 J/kg of MUCAPE is responsible
for the non-zero chances. Highest probabilities and spatial
coverage for showers and thunderstorms are expected during the
afternoon hours when instability is highest, and decreasing into
the evening and overnight hours as instability wanes. With
precipitable water remaining above 1.75", locally heavy rainfall
can`t be ruled out.

As for temperatures, expect them to slowly increase into the
middle of the week given the persistent pattern underneath the
aforementioned upper level high. NAEFs and ECMWF ensemble
situational awareness tables (ESATs) continue to show the region
remaining near/above the 90th percentile of climatology with
respect to geopotential heights from 850mb up to 200 mb,
resulting in afternoon highs in the lower to mid 90s on each
day, while those near the coast remain in the mid/upper 80s.
Heat index values in the mid 90s to lower 100s are also
expected, possibly as high as mid to upper 100s if higher
dewpoints in the upper 70s are realized. Best chances appear to
be on Wednesday as that is when highest temperatures are
possible due to the ridge building aloft.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/...
The aforementioned pattern continues while the upper level
ridge begins to slowly build/shift westward as a weak trough
moves into the northeast Thursday into Friday. Temperatures
remain largely in the lower to mid 90s, with daily chances for
showers and thunderstorms continuing.

Behind the exiting upper level trough, deterministic and
ensemble models show a ridge building aloft as it moves
westwards towards the east coast. At the surface, some guidance
continues to show a weak front and low pressure move down from
the Ohio River Valley, though the majority of guidance does not
include that feature...however, this mismatch is leading to NBM
temperatures coming in a touch cooler than expected. Would not
be surprised to see later runs of the NBM bring temperatures
closer to the mid to upper 90s over the weekend, closer to what
the 90th percentile is showing.

&&

.AVIATION /16Z SUNDAY THROUGH THURSDAY/...
15/18z Aviation Discussion:
KCHS/KJZI/KSAV: VFR will prevail for much of the period.
Scattered showers/tstms are expected again this afternoon, but
current data suggest the bulk of the activity will remain just
west of all terminals. It could get close to KSAV and possibly
KCHS later in the afternoon. VCTS was highlighted to reflect
this. Convection will wane this evening.

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

&&

.MARINE...
Today and Tonight: No highlights are expected for this period.
The waters will remain between deep layer ridging to the
southeast and a broad trough well to the west. This will
continue southwest winds of 10-15 knots. Winds could gust up to
near 20 knots near the mouth of Charleston Harbor this
afternoon. Seas 2 to 4 feet, highest beyond 10 nm offshore.There
will also continue to be a longer period swell from the
southeast.

Monday through Friday: Typical summertime conditions will
prevail over the waters with high pressure centered offshore of
the Southeast States. A broad, southerly wind regime can be
expected with winds generally averaging 15 kt or less, except a
bit higher along the land/sea interface and Charleston Harbor
each afternoon with the sea breeze. Seas will remain 4 ft or
less through the period.

Rip Currents: An easterly swell surge will arrive along the
Charleston County beaches today and all remaining beaches for
Monday. This coupled with locally breezy conditions near the
afternoon sea breeze will support a moderate rip current risk for
all beaches today and Monday.

&&

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

&&

$$