040
FXUS62 KCHS 060600
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
200 AM EDT Sun Jul 6 2025

...STRENGTHENING CHANTAL APPROACHING THE MIDDLE SOUTH CAROLINA
COAST...

.SYNOPSIS...
Tropical Storm Chantal is forecast to move onshore the South
Carolina coast early this morning. Weak high pressure will then
rebuild across the area and prevail through the upcoming week.

&&

.NEAR TERM /THROUGH TONIGHT/...
The expectation is that the Tropical Storm Watch for Charleston
County will be cancelled with either the 5 AM advisory or the 8
AM intermediate advisory from NHC.

Today: Tropical Storm Chantal is approaching the middle South
Carolina early this morning and should be inland prior to
daybreak with a most likely landfall occurring somewhere along
the far upper Charleston County or Georgetown County coast.
Chantal remains asymmetric based on satellite, radar and
earlier reconnaissance aircraft data given the ongoing shear
aloft. This will help keep the bulk of the tropical cyclone`s
impacts displaced along and to the northeast of where the center
tracks. Any significant issues will therefore remain confined
to the upper South Carolina coast and Pee Dee with little in the
way of significant impacts to the Lowcountry. Breezy conditions
will persist across the central and upper Charleston County
coast for the next few hours with winds expected to diminish
as daybreak and especially mid-morning approaches.

As Chantal moves north across the Pee Dee into North Carolina,
several bands of showers and possibly tstms should redevelop
across the area once morning low clouds mix out and instability
begins to build with daytime heating. The best coverage should
occur across mainly the Lowcountry where ripples of low-level
convergence should occur along the south and southwest flanks of
the low-level circulation. This scenario is reflected rather
well in the latest simulated reflectivity progs from the various
CAMS. The forecast will continue to utilize the 06/01z NBM for
hourly pops, but similar to yesterday, its output looks a bit
aggressive with some degree of subsidence likely to linger on
the outer periphery of Chantal`s broad circulation. The 06/00z
HREF and CAMs certainly favor a drier overall solution, but no
local modifications were made given they do meet the new,
national "break the glass" criteria. Pops will range from 60%
across Berkeley and Dorchester Counties with 30-50% across the
remainder of Southeast South Carolina and Southeast Georgia.
Extensive cloud cover over the Lowcountry will help limit highs
this afternoon, even as clouds begin to mix out later this
morning. This will have an impact on afternoon highs. Highs look
to range from the mid 80s across the Lowcountry with upper
80s/lower 90s over Southeast Georgia. It will be a bit cooler at
the beaches with high warming into the mid-upper 80s with
offshore flow prevailing for much of the day before low-level
winds begin to back to the southwest.

Lake Winds: Winds have risen over Lake Moultrie over the past
few hours as Chantal draws closer to the coast. Winds at PNOS1
along the south side of Lake Moultrie has been averaging 20 kt
with gusts 25-30 kt over the past few hours. Given this trend, a
Lake Wind Advisory has been posted through 5 AM. This may be a
tad long, but will align with a required update for the 5 AM NHC
advisory.

Tonight: Any lingering isolated shower/tstm activity will
dissipate early in the evening as Chantal weakens and moves
farther away from the area. Some lingering feeder bands could
redevelop over the Atlantic late which could brush the upper
portions of Charleston County; however, most areas should remain
rain-free through the night. Lows will range from the lower 70s
well inland to around 80 at the beaches.

&&

.SHORT TERM /MONDAY THROUGH WEDNESDAY/...
Remnants of Tropical Storm Chantal will continue to pull
northward away from the region Monday, with the surface pattern
to then feature high pressure offshore with a trough of low
pressure inland. Shower and thunderstorm coverage will be scant
Monday (POPs ~10- 25%), as the axis of highest moisture shifts
northward. Model soundings also indicate subsidence in the wake
of the departing low Monday, becoming more subtle by Tuesday.
Therefore there could be slightly greater shower/tstm coverage
Tuesday afternoon, increasing for Wednesday afternoon as the
area transitions into a seasonable pattern. High temperatures
will jump back in the mid to upper 90s Monday and Tuesday with
mostly sunny skies forecast. With accompanying dew points
nearing the mid 70s, heat indices in a few spots could make a
run for Heat Advisory criteria (108F degrees), mainly Tuesday.
Both nights will be mild with min overnight temperatures only in
the mid to upper 70s. Wednesday should see highs about 1-2
degrees cooler with increased convection.

&&

.LONG TERM /WEDNESDAY NIGHT THROUGH SATURDAY/...
Weak flow within subtle ridging aloft will persist along with
no discernible synoptic features. Therefore, the forecast will
be dominated by a typical summertime sea breeze pattern, with
scattered showers and thunderstorms possible each day especially
in the afternoon and early evening when instability is
maximized. Highs are forecast to remain in the low/mid 90s
inland of the coast.

&&

.AVIATION /04Z SUNDAY THROUGH THURSDAY/...
06/06z TAF Discussion:
KCHS/KJZI: MVFR cigs expanding across the Lowcountry are
expected to lower into the IFR range over the next few hours at
both terminals. Cigs are expected to remain above alternate
minimums. Cigs should begin to mix out and lift by mid-morning
with VFR returning by early afternoon. Bands of light rains
associated with Chantal may meander near or just to the
north/northeast of terminals this morning, but may briefly
impact just before daybreak. VCSH was maintained to account for
this. Other bands could develop near both airports by early
afternoon as daytime heating and instability build. Confidence
for direct impacts is low with high-res data supporting a number
of possible outcomes of where bands will set up. VCSH was
highlighted for the afternoon hours.

KSAV: VFR should prevail for much of the period. A period of
MVFR cigs could move in from the north by mid-morning and
linger for a few hours before returning to MVFR. Timeframe from
15-19z looks the most likely for MVFR cigs.

Extended Aviation Outlook: Brief ceiling/vsby restrictions
possible due to scattered showers and thunderstorms closer to
mid week.

&&

.MARINE...
Today: Conditions will steadily improve across the waters today
as Chantal moves inland. Based on the latest forecast and
observations, the following changes were made to marine
advisories and warnings:

* Continue Tropical Storm Warning for the South Santee-Edisto
  Beach nearshore leg for a few more hours until Chantal is
  inland.
* Downgrade the Tropical Storm Warning to a Small Craft Advisory
  through 8 AM for the Edisto Beach-Savannah nearshore leg. This
  is mainly to account for lingering 6 ft seas and northwest
  winds 15-20 kt with gusts to 30 kt.
* Cancel the Small Craft Advisory for the Savannah-Altamaha
  Sound out 20 NM leg given winds and seas have dropped below
  advisory thresholds.
* Extend the Small Craft Advisory for the Savannah-Altamaha
  Sound out 20-60 NM offshore leg through 8 AM given lingering 6
  ft seas.
* Extend the Small Craft Advisory through 5 AM for Charleston
  Harbor where winds remain above 20 kt. The Tropical Storm
  Watch will remain in place until Chantal makes landfall.

Tonight: Southwest winds will persist in the wake of Chantal
with speeds averaging 10-15 kt over the Georgia waters and 15-20
kt over the South Carolina waters. Seas will subside 2-4 ft,
except 3-5 ft over the South Santee-Edisto Beach nearshore leg.

Monday through Friday: Relatively benign conditions will
persist through the period as winds settle into a SW flow with
the Tropical Storm, or the remnants of, Chantal located to the
north and high pressure to the east. No marine
concerns/headlines expected during the period with winds 15 kt
or less and seas 2-4 ft.

Rip Currents: A Moderate Risk for rip currents exists for all
area beaches due to residual swell. Lingering swell will result
in a Moderate Risk of rip currents for the Charleston/Colleton
County beaches.

High Surf: The risk for breakers of 4-6 ft in the surf zone will
persist across upper Charleston County for a few more hours. The
High Surf Advisory continue through 8 AM.

&&

.CHS WATCHES/WARNINGS/ADVISORIES...
GA...None.
SC...Tropical Storm Watch for SCZ050.
     Lake Wind Advisory until 5 AM EDT early this morning for
     SCZ045.
     High Surf Advisory until 8 AM EDT this morning for SCZ050.
MARINE...Small Craft Advisory until 5 AM EDT early this morning for
     AMZ330.
     Tropical Storm Watch for AMZ330.
     Tropical Storm Warning for AMZ350.
     Small Craft Advisory until 8 AM EDT this morning for AMZ352-
     374.

&&

$$