Sumter, South Carolina 7 Day Weather Forecast

Wx Forecast - Wx Discussion - Wx Aviation

894
FXUS62 KCAE 200637
AFDCAE

Area Forecast Discussion
National Weather Service Columbia SC
237 AM EDT Thu Aug 20 2026

.WHAT HAS CHANGED...
Forecast remains on track for widespread storms on Friday with
flash flooding and damaging winds being the main threats.

&&

.KEY MESSAGES...
- 1. Severe weather and flash flooding possible Friday.

&&

.DISCUSSION...
KEY MESSAGE 1: Severe weather and flash flooding possible
Friday.

Upper troughing amplifies over the eastern US Friday promoting
SW flow into the forecast area. PWAT values rise to near or
above 2 inches by the afternoon as surface low pressure develops
near the area. Convergence along a surface boundary over the
Carolinas will serve as the focus for thunderstorms in the
afternoon as the air mass destabilizes. mlCAPE values should
range from 1000 to 2000 J/kg over the area with highest values
in the eastern Midlands and Pee Dee. Steep low level lapse rates
and height falls will support strong updrafts and the potential
for damaging winds. Models have trended lower on shear values
indicating less potential for organized storms but higher
potential for flash flooding given overall slower storm
movement. The threat of localized flooding should be highest in
the northern Midlands and Pee Dee, closest to the surface
boundary. The REFS indicates the most likely timing for severe
weather will be between 3 PM and 7 PM but the threat could
extend into the evening depending on the timing of shortwaves
passing through the broader trough. As the upper trough axis
slowly moves through the area Saturday, the bulk of the
convective activity should shift to the east with drier air
moving into the area from the west.

Otherwise, today atmospheric moisture remains relatively
limited with just isolated to widely scattered storms expected
in the eastern Midlands and Pee Dee. Although we cannot rule
out an isolated damaging downburst chances are low. Cooler
weather is likely next week with temperatures closer to normal
along with seasonal, diurnal thunderstorm chances.

&&

.AVIATION /06Z THURSDAY THROUGH MONDAY/...
VFR conditions expected to persist through Thursday outside of
possible convection.

Clear skies and quiet conditions are occurring tonight. Low
level moisture is quite robust across the area, with mid 70s
dewpoints present. This could lead to some patchy ground fog
especially at OGB which is prone to ground fog anyways. As we
get into the day today, VFR cumulus will likely develop by early
afternoon as southerly winds continue to push moisture into the
area. Convection is possible this afternoon and evening but
coverage and timing are quite uncertain across the area.
CAE/CUB/OGB have the best chances for showers/storms and have
added a basic Prob30 group for showers to account for this
possibility.

EXTENDED AVIATION OUTLOOK...Thunderstorm chances increase
Friday and Saturday with scattered to widespread convection
expected.

&&

.CAE WATCHES/WARNINGS/ADVISORIES...
SC...None.
GA...None.

&&

$$

DISCUSSION...CJR
AVIATION...PL