402
FXUS62 KCAE 221121
AFDCAE

Area Forecast Discussion
National Weather Service Columbia SC
721 AM EDT Fri Aug 22 2025

.SYNOPSIS...
Scattered to widespread showers and storms today and Saturday
with the potential for heavy rain and localized flash flooding
each day. Cooler temperatures area also expected today and
tomorrow due to developing upper troughing. Shower and storm
chances then begin to diminish beginning Sunday. After a brief
warm up to start the week, drier and cooler air pushes into the
region for the rest of the week after the passage of a cold
front.

&&

.NEAR TERM /THROUGH TONIGHT/...
Key Message(s):

- Heavy rainfall possible, especially in the southeastern
  Midlands and CSRA with isolated flash flooding possible.
- Cooler today with extensive cloud cover

Some lingering showers continue across the region early this
morning as a weak boundary sinks southward through the forecast
area. As Erin moves away from the Mid-Atlantic coast weak upper
troughing will sink southward over the Carolinas and across the
Gulf Coast states.

NAEFS ESAT continues to show PWATs at or above the 90th
percentile with values exceeding 2 inches across the forecast
area which will lead to heavy rainfall potential and a flash
flooding risk. Overall flow in the atmosphere will be generally
light with weak shear and lead to slow moving convection and
possible training of storms and result in very efficient
rainfall rates. WPC continues to outlook the southern part of
the forecast area including the CSRA and southeast Midlands in a
slight risk of excessive rainfall.

Hi-res guidance suggests some isolated showers in the morning
becoming more widespread this afternoon across the southern half
of the forecast area in the vicinity of the stalled frontal
boundary which will provide low level convergence. Weak upper
troughing and a possible shortwave will provide weak upper level
forcing as well supporting high chances of rain this afternoon
and evening favoring the CSRA and southeast Midlands, with lower
chances across the northern Midlands. HREF LPMM continues to
highlight the southeast Midlands for possible significant
rainfall due to slow moving storms with localized amounts of 4
to 6 inches possible. Flood watch takes effect this morning
through Saturday night. Temperatures should be much cooler today
with extensive cloud cover expected and associated rainfall with
highs ranging from around 80 to the mid 80s. Convection may
linger into the evening and overnight hours due to the weak
upper troughing and stalled boundary. Overnight lows expected to
also be cooler in the upper 60s to lower 70s.

&&

.SHORT TERM /SATURDAY THROUGH SUNDAY NIGHT/...
Key message(s):

- Heavy rain threat continues for Saturday with potential for flash
  flooding in the CSRA to southern Midlands.
- Drier air begins moving in on Sunday, but scattered showers and
  storms remain possible.

Saturday: Upper shortwave trough over remains over the area
Saturday. Meanwhile, a meandering surface boundary is expected to
stay near the area, with guidance suggesting that it drifts a little
farther south and reorients to more southwest to northeast for
Saturday. With the exception of this shift of the surface boundary,
the airmass is not forecast to be much different from Friday. PWATs
are forecast to be generally in the 2-2.25" range with highest
amounts in the southeastern portions of the forecast area. Forecast
soundings also show long-skinny CAPE for most areas in the region.
All of this suggests that there is a threat for heavy rain with
potential for flash flooding. The highest chances for this on
Saturday are in the lower CSRA into the southern Midlands. Thus,
there is a Flash Flood Watch that continues through the day
Saturday. With the rain and likely cloud cover, temperatures are
expected to be on the cool side for this time of year.

Sunday: A larger scale upper level trough translating from the Upper
Midwest into the Great Lakes is forecast to phase with the shortwave
trough over the Southeast for the second half of the weekend. As a
result, the lingering boundary is forecast to begin pushing
eastward. This is expected to lead to an initial push of drier air
along with less coverage of showers and storms across the area. In
addition, temperatures are forecast to be a few degrees warmer on
Sunday compared to Saturday.

&&

.LONG TERM /MONDAY THROUGH THURSDAY/...
Key message(s):

- Drier air along with cooling temperatures through the long term.

General upper level troughiness remains over the region through the
long term period. Shortwave energy rotating around this trough is
anticipated to bring even drier air into the area with decreasing
chances for showers and storms as the week progresses. Monday is
forecast to be around average for this time of year before a cooling
trend for the remainder of the forecast period.

&&

.AVIATION /11Z FRIDAY THROUGH TUESDAY/...
A mix of conditions expected through the forecast period.

Abundant low level moisture and upper troughing over the region
along with a stalled boundary are leading to scattered showers this
morning. There have been intermittent MVFR cigs and satellite
imagery showing a blanket of MVFR cigs sinking southward from NC
into the northern Midlands and expect this to impact terminals with
MVFR cigs through early afternoon. Another round of convection is
expected this afternoon and evening with possible heavy rain at
times and will carry a PROB30. Winds should remain light through mid
morning less than 5 mph then pick up from the east around 5 to 10
mph through the afternoon before dropping off again after sunset.
More stratus seems likely tonight with little change in air mass and
continued high levels of moisture in place.

EXTENDED AVIATION OUTLOOK...Restrictions again expected on Saturday
as deep moisture remains over the region. Showers and thunderstorms
are also likely on Saturday afternoon. A drier air mass will arrive
behind on front on Monday.

&&

.CAE WATCHES/WARNINGS/ADVISORIES...
SC...Flood Watch through late Saturday night for SCZ018-025-030-035-
     041-135>137.
GA...Flood Watch through late Saturday night for GAZ040-063>065-077.

&&

$$

SYNOPSIS...
NEAR TERM...
SHORT TERM...
LONG TERM...
AVIATION...