956
FXUS62 KCHS 011059
AFDCHS

Area Forecast Discussion
National Weather Service Charleston SC
659 AM EDT Fri Aug 1 2025

.SYNOPSIS...
A cold front slides towards the area to end the week, moving
south of the region this weekend before stalling into next
week.

&&

.NEAR TERM /THROUGH TONIGHT/...
Rest of this morning: Scattered convection that was west of our
forecast area over the SC Midlands, has continued to rapidly
dissipate at is moves eastward. Although there is ample
instability and low level moisture, model soundings indicating a
low level inversion, which is likely causing convection to die
down as it moves across our area. With that said, can`t rule out
a stray shower or thunderstorm for the next few hours. Low
temperatures are expected to be very warm, generally in the
upper 70s to low 80s most areas, which are record high minimum
levels. However, convection later this afternoon/evening will
likely knock down temperatures below record levels.

This afternoon and evening: The pattern starts to get more
active as a weak surface front sags southward into the northern
part of SC by evening. Ahead of this feature, deep layer
moisture pooling and low level convergence is expected to
produce scattered to numerous showers and thunderstorms. There
is a bit more westerly shear this afternoon, which may support
isolated strong to severe storms, especially where boundaries
collide. Main threat from any stronger storms will be gusty
straight line winds, given DCAPEs of 1000+ J/Kg. Also, locally
heavy rainfall will be possible, especially over our SE SC
zones, including cities of Charleston and Beaufort. Despite
increased chances for convection, still there will be enough
heating to once again produce max afternoon heat indices of
108-112, especially closer to the coast. Expanded the Heat
Advisory to cover our ENTIRE area for this afternoon.

Tonight: HREF solution indicates that scattered to numerous
showers and thunderstorms will linger well into the evening,
before finally decreasing later at night as the surface front
continues to sag southward. Locally heavy rainfall and and
isolated strong/severe storm will be possible into the evening.
By late night, the leading edge of the front could make it to at
least the Savannah River, and then possibly to just north of the
Altamaha River, GA by daybreak. Low level NE winds will help to
bring down slightly cooler air, with lows by morning in the
lower to mid 70s,closer to normal.

&&

.SHORT TERM /SATURDAY THROUGH MONDAY/...
Big pattern shift continues into the weekend as the ridge of high
pressure is pushed southwards, bringing much cooler temperatures to
the region and leading to numerous chances for rainfall. We`ll have
to see exactly where the front ends up by Saturday morning due to
the expected overnight convection, though current indications are
for the front to be draped from west to east across our southeastern
Georgia counties.  This sets the stage for the South Carolina
Lowcountry to only see afternoon highs reaching up into the 80s,
while extreme southeast Georgia south of I-16 will likely see highs
in the upper 80s to lower 90s.

While the front will bring cooler temperatures, it is expected to
have pooled/amassed a fair bit of moisture on its southern
periphery. Ensemble situational awareness tables (ESATs) show right
around 2 inches of PWATs, which is just at the 90th percentile of
model climatology for the time period is spread out along the front.
The ECMWF Extreme Forecast Index does show some areas along coastal
southeast South Carolina and coastal southeast Georgia along with
inland in the 0.6-0.7 range, indicative of a wetter than normal
period expected, while a smaller area of 0.7-0.8 is forecast across
southeast Georgia. There is also a shift of tail contour of zero
showing up, indicating that at least 10% of the ensemble members are
forecasting above model climate, increasing confidence in locally
heavy rainfall being possible. 01.00Z HREF indicates area along and
south of the SC/GA border and across southeast Georgia have the
greatest chance at seeing an inch of rain (40 km neighborhood radius
has 90% probabilities), with the 50% contour for 3 inches similarly
hugging the SC/GA border and expanding southwards. Due to the threat
of heavy rainfall, WPC maintains their slight (level 2 out of 4)
risk for excessive rainfall across coastal South Carolina and
Georgia, with a marginal (level 1 out of 4) risk across inland
counties.

Overnight into Sunday, the front transitions into more of an
inverted trough extending from the Gulf into southeast Georgia and
out into the Atlantic. This will continue to act as a focus for
rainfall Sunday and Monday, so can`t rule out an isolated locally
heavy rainfall threat, especially for areas that do end up seeing
those higher rainfall totals on Saturday. As for temperatures,
afternoon highs in the lower to upper 80s are expected.

&&

.LONG TERM /MONDAY NIGHT THROUGH THURSDAY/...
Ridging attempts to build back across the region as a trough moves
out of the central US and towards the east coast throughout the
week. This will result in periodic chances for rain, with seasonal
temperatures in the upper 80s to lower 90s expected to build back
into the region.

&&

.AVIATION /12Z FRIDAY THROUGH TUESDAY/...

Today: VFR will prevail into the early afternoon. Then scattered
to numerous showers and thunderstorms with periodic flight
restrictions will become more likely at all terminals later this
afternoon and into the evening, especially for KCHS and KJZI.
Isolated strong to severe storms will be possible, with strong
gusty winds and heavy downpours.

Tonight: Scattered showers and thunderstorms, along with the
potential for flight restrictions will persist well into the
evening. After midnight, expect chances of convection to be
less. The low level flow will veer to NNE for KCHS and KJZI late
as a cold front sags southward. MVFR to near IFR CIGS possible
late, but have continued MVFR CIGS all sites for now due to
uncertainty with position of the surface front.

Extended Aviation Forecast: As a reasonably strong cold 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 this morning and into this afternoon: The pressure
gradient continues to be pinched closer to the coast across
AMZ350 and 352, with gusts of 20-25 knots. Expect this gradient
to slowly weaken toward sunrise, with generally SSW winds of
10-15 knots and seas 2 to 3 feet. Scattered to numerous showers
and thunderstorms by later in the afternoon, ahead of a cold
front sagging southward.

Tonight: The cold front is expected to reach the southern part
of our GA waters toward sunrise Saturday. The front will veer
winds from SW to NNE at 10 to 15 knots, and 5 to 10 knots over
our southern GA waters late. Seas remain generally 2 to 3 feet.

Saturday: Saturday will see chances for showers and thunderstorms
increase throughout the day, with northeast winds also increasing to
10 to 15 knots across coastal South Carolina and up to 10 across
coastal Georgia, gusting to near 20 knots. Wave heights of 2 to 3
feet.

Sunday into Tuesday: Swells will be increasing into the beginning of
the week, first starting out in the waters from South Santee River
to Edisto Beach SC and last from Savannah to Altamaha Sound GA, with
daily chances for showers and thunderstorms continuing. Northeast
winds will increase further on Sunday, sustained in the lower to
upper teens with gusts up into the teens to lower 20s, strongest
across coastal and offshore South Carolina Waters. Expect much of
the same on Monday, with winds beginning to weaken on Tuesday.

&&

.CLIMATE...
KCHS has tied the record low min for July 31, which was 80, last
set in 2022.

Record High Minimum Temperatures:

August 1:
KCHS: 81/1999
KSAV: 79/2020

Record Precipitation:

August 2:
KSAV: 1.81/1990

&&

.CHS WATCHES/WARNINGS/ADVISORIES...
GA...Heat Advisory from 11 AM this morning to 8 PM EDT this evening
     for GAZ087-088-099>101-114>119-137>141.
SC...Heat Advisory from 11 AM this morning to 8 PM EDT this evening
     for SCZ040-042>045-047>052.
MARINE...None.

&&

$$

NEAR TERM...RFM
SHORT TERM...APT
LONG TERM...APT
AVIATION...RFM
MARINE...APT/RFM