769
FXUS62 KCHS 052248
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
648 PM EDT Tue Aug 5 2025

.SYNOPSIS...
A front will linger near or just south of the area this week,
while high pressure remains centered well to the north. Low
pressure could develop off the Southeast U.S. coast on Thursday
and persist into the weekend.

&&

.NEAR TERM /THROUGH WEDNESDAY/...
Convection has consolidated into a broad line from Walterboro
south to Hilton Head. This activity will move into the
Charleston Tri-County shortly, but will mainly target areas
south of a Summerville-Awendaw line, including Downtown
Charleston. Instability is still modest ahead of the line
(MLCAPE ~1500 J/kg) but is diminishing with time. While tstm
intensity should slowly wane, a risk for strong winds and
flooding will persist for a few more hours. Pockets of flash
flooding is also possible, especially for lower and central
Charleston County, including in the typical flood-prone area of
Downtown Charleston.

Tonight: The mid-levels will consist of a trough across the
Midwest, with an axis extending into the Deep South. At the
surface, our area will remain between a stationary front to our
south and High pressure to our north. Convection could persist
overnight over land areas. Though, it should be isolated to
scattered in coverage. Otherwise, the bulk of the convection is
expected to remain offshore. Some could brush along the
immediate coast. Lows will be in the upper 60s well inland to
the mid 70s near the coast.

&&

.SHORT TERM /WEDNESDAY NIGHT THROUGH FRIDAY/...
Short term guidance indicates a H5 trough advancing across the
Southeast U.S. on Wednesday. At the sfc, a ridge should remain
centered over the western Carolinas, with a wavy stationary front
along the coast. SBCAPE is forecast to increase between 2000-3000
J/kg along the coast, especially if a coastal trough develops.
Latest run of the HREF and HRRR, thunderstorms should develop in the
afternoon along the sea breeze, especially along the SC coast.
During the rest of the afternoon and evening, numerous to widespread
showers and thunderstorms should advance inland. High temperatures
are forecast to range from the upper 80s along the coast the mid 80s
inland.

Thursday and Friday, the forecast area is forecast to remain in a
weakness, between a ridge over the western Atlantic and another
ridge centered over Southern Plains. Each afternoon, a weak sea
breeze should develop during the afternoon, pushing inland through
the evening. In addition, NHC has highlighted the Southeast U.S.
Atlantic waters with a 40 percent chance of tropical cyclone
formation over the next 7-days. WPC sfc pressure maps indicate that
the spot the low is expected to remain off shore off the GA/SC
coast. High temperatures are forecast to range in the mid to upper
80s. Low temperatures should favor values in the 70s.

&&

.LONG TERM /FRIDAY NIGHT THROUGH TUESDAY/...
This weekend, uncertainty remain high, but the low off the coast
should track to the north. The forecast area should remain under
deep moisture, PW values around 2 inches. Starting early next week,
H5 ridging should increase across the region, with 595 dm H5 heights
across the region by Tuesday. Scattered to numerous showers and
thunderstorms are possible each afternoon and evening. Temperatures
should gradually warm through the period, with highs ranging in the
90s by Tuesday.

&&

.AVIATION /00Z WEDNESDAY THROUGH SUNDAY/...
06/00Z TAF Discussion:
KCHS/KJZI: Convection south of KRBW will approach both terminals
around the 00z TAF time. Activity should slowly weaken as it
approaches, but tstms impacts appear likely. The best push will
be at KJZI where some IFR vsbys in TSRA may occur. Up at KCHS,
conditions look to favor more MVFR vsbys in TSRA right now.
TEMPO groups were highlighted through 02z to account for this.
Some last minute adjustments may be needed pending trend at
issuance time. Once rain diminishes, cigs should settle into
MVFR thresholds overnight. VFR will return by mid-morning. Risk
for tstm impacts will increase by early afternoon as the sea
breeze becomes a focus for convection which may meander near
both terminals for much of the afternoon hours.

KSAV: The heaviest of the convection has cleared the terminal.
Mostly light rain will persist for a few more hours. There is a
risk for MVFR cigs forming prior to daybreak, but its extent and
timing is a bit uncertain with guidance hinting at a number of
possible scenarios. VFR should return by mid-morning. The risk
for tstm impacts will increase mid/late afternoon as the sea
breeze meanders inland.

Extended Aviation Forecast: As a front stalls nearby this weekend,
brief flight restrictions will be possible as showers and/or
thunderstorms develop along this boundary through early next
week.

&&

.MARINE...
Rest of Today and Tonight: Our coastal waters remain sandwiched
between a stationary front to our south and High pressure to
our north. This will support E to NE winds sustained at 5-10 kt,
easing late tonight. Seas will be 2-4 ft this evening, subsiding
to 1-3 ft overnight.

Wednesday through Sunday: The sfc pattern will support steady
northeast winds between 10-15 kts, with occasional gusts to 20 kts.
Wave heights should generally range between 2 to 3 ft. In addition,
NHC has highlighted the Southeast U.S. Atlantic waters with a 40
percent chance of tropical cyclone formation over the next 7-days.
WPC sfc pressure maps indicate that the spot the low is expected to
remain off shore off the GA/SC coast.

&&

.TIDES/COASTAL FLOODING...
As we approach Full Moon on August 9th, the evening high tide
will be rising above/near 6.5 ft MLLW (action stage) at the
Charleston tide gauge, while remaining well below action stage at
the Fort Pulaski tide gauge. Minor coastal flooding may be possible
on Thursday and Friday along the Charleston coastline.

&&

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

&&

$$