Flash Flood Warning 13, NWS Columbia, SC

Area Forecast Discussion
National Weather Service Columbia SC
119 PM EDT Mon Jul 13 2026

.WHAT HAS CHANGED...
Little change in the thinking with a locally heavy rainfall
threat this afternoon and evening. Aviation discussion updated
for 18z TAF.

&&

.KEY MESSAGES...
- 1. Scattered to widespread showers and storms expected this
  afternoon, continuing into the early overnight. A couple
  strong to marginally severe storms will be possible along with
  isolated spots of flash flooding. Lingering moisture leading
  to scattered to widespread afternoon storms Tuesday and
  Wednesday.

&&

.DISCUSSION...
Key Message 1: Scattered to widespread showers and storms
expected this afternoon, continuing into the early overnight. A
couple strong to marginally severe storms will be possible along
with isolated spots of flash flooding. Lingering moisture
leading to scattered to widespread afternoon storms Tuesday and
Wednesday.

Overall, there has not been much change in the outlook for
the rest of the today based on 18z observations and updated hi-
res guidance. A slow moving surface front is gradually working
south through the FA and will eventually stall across the I-20
corridor and CSRA. Mean sfc-400mb flow out of the southwest
should advect PWAT's 1.5-2 standard deviations above normal
(~2.20-2.40"), creating very moist profiles. With surface
dewpoints remaining in the low to mid 70s, mean HREF soundings
indicate SBCAPE values between 1500-2000 J/kg should develop
through the day, less than previous days mostly due to cooler
surface temperatures ranging from the low 80s north to the mid
to upper 80s south. With more moist adiabatic profiles, DCAPE is
progged to be less than previous day's as well. An uptick in
kinematics from the mid level low should bring increased shear
(EBWD ~20-25 kts) though, so a few strong to marginally severe
storms remain possible during the afternoon/early evening with
the main hazard being damaging wind gusts from precip- loaded
downdrafts. Activity likely carries into the overnight, but the
severe risk is expected to diminish during this period.

The bigger talking point is the heavy rainfall potential
through the afternoon and evening. The 12z guidance has followed
well with current observations, continuing the threat for
locally high rainfall amounts later today. These moist
adiabatic profiles, long/skinny CAPE, a nearly stationary front,
and the aforementioned PWAT's should act to bring quite
efficient rainfall rates and the potential for training
convection. The HREF 24hr QPF LPMM product indicates a fairly
widespread 0.50-1.0" is a reasonable expectation, but it does
indicate spots of 2-5" being possible, which is further
supported in deterministic CAMs and the 12z REFS LPMM; even 6hr
LPMM indicates over 5" possible in highly localized spots.
There is lesser confidence in the exact placement of higher QPF
amounts with some spatial variability amongst deterministic
CAMs, but with the frontal boundary expected to nearly stall in
the southern FA, this could be an area to watch more closely.
Areas in the southeastern Midlands near eastern Bamberg County
into Orangeburg and southern Calhoun Counties saw 1-3" of
rainfall from Sunday's activity so these spots would be the most
sensitive to additional higher amounts. Overall, isolated
instances of flash flooding will be possible if these higher
amounts are realized.

Scattered shower and thunderstorm chances will likely continue
Tuesday and Wednesday as ensemble meteograms indicate PWAT's
near to over 2" remain in place through at least the first half
of Wednesday. As the mid level low slowly retrogrades, drier air
may begin pushing into the Pee Dee and northern Midlands
Wednesday, bringing lower rain chances here. Cooler than normal
temperatures are also expected to persist through Wednesday
before gradually warming during the second half of the week back
to near normal. Typical diurnal rain chances could make an
appearance late in the week into next weekend, but there is
generous spread in LREF cluster analysis at this point.

&&

.AVIATION /18Z MONDAY THROUGH SATURDAY/...
A mix of MVFR and VFR conditions are expected this afternoon and
evening, with showers and storms helping that. Widespread MVFR
and IFR ceiling restrictions are expected tonight.

The slow moving front is currently sagging southward across the
area. Cooler low-level air and northeasterly flow north of this
feature has led to a morning filled with MVFR restrictions,
with these slowly lifting now. Expecting convection to quickly
fill in along this front, with heavy rainfall expected in any
thunderstorm that passes over a site. The best chances for
storms in the next few hours are at the Columbia sites, with the
Aiken, Augusta, and Orangeburg sites seeing convection either
develop or move in later this afternoon and evening.
Restrictions are expected with any storm that does develop.
Variable winds are forecast to remain in place this afternoon
and into tonight, with potentially more persistent northeasterly
flow arriving tonight. Given expectation of rain coverage today
& already moisture rich airmass in place, guidance is quite
aggressive with cig forecast tonight, showing IFR developing
quickly after sunset. This makes sense from a pattern
recognition standpoint and have the forecast reflecting such.
Expecting that MVFr/IFR cigs will hold on into the midday on
Tuesday.

EXTENDED AVIATION OUTLOOK...A good chance for afternoon showers
and thunderstorms with associated restrictions is expected
through at least Tuesday.

&&

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

&&

DISCUSSION...42
AVIATION...PL

Special Weather Statement
National Weather Service Columbia SC
610 PM EDT Mon Jul 13 2026

SCZ030-035-041-135-136-132245-
Central Orangeburg SC-Barnwell SC-Aiken SC-Bamberg SC-
Northwestern Orangeburg SC-
610 PM EDT Mon Jul 13 2026

...A strong thunderstorm will impact portions of northeastern
Barnwell, northwestern Bamberg, southeastern Aiken and west central
Orangeburg Counties through 645 PM EDT...

At 610 PM EDT, Doppler radar was tracking a strong thunderstorm near
Williston, or 9 miles north of Barnwell, moving north at 10 mph.

HAZARD...Wind gusts up to 50 mph and pea size hail.

SOURCE...Radar indicated.

IMPACT...Gusty winds could knock down tree limbs and blow around
         unsecured objects. Minor damage to outdoor objects is
         possible.

Locations impacted include...
Barnwell, Williston, Blackville, Barnwell State Park, Springfield,
Hilda, Elko, Windsor, Aiken Gopher Tortoise Heritage Preserve, and
Barnwell County Airport.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

If outdoors, consider seeking shelter inside a building.

Torrential rainfall is also occurring with this storm and may lead to
localized flooding. Do not drive your vehicle through flooded
roadways.

&&

LAT...LON 3323 8118 3329 8165 3353 8148 3350 8116
TIME...MOT...LOC 2210Z 192DEG 10KT 3338 8137

MAX HAIL SIZE...0.25 IN
MAX WIND GUST...50 MPH

DH

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