534
FXUS62 KCAE 200721
AFDCAE

Area Forecast Discussion
National Weather Service Columbia SC
321 AM EDT Sat Jul 20 2024

.SYNOPSIS...
A frontal boundary will be stationary across the region for the
next several days with increased shower and thunderstorm
activity mainly in the afternoon and evening hours. Some
locally heavy rainfall is possible which could result localized
flash flooding and rising levels in area rivers. Temperatures
will be near to slightly below through the middle of next week.

&&

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

- Lingering showers dissipate this morning.
- Low clouds and/or patchy fog give way to partly sunny skies.
- Scattered showers and thunderstorms develop later today which
  may produce heavy rainfall and localized flash flooding.
- A few thunderstorms may become strong to severe with gusty
  winds as the primary severe hazard.

Radar imagery early this morning shows light showers across our
western counties. These should continue to dissipate as the
night goes on. Primary concern tonight will be the potential for
low clouds and/or patchy fog, especially in locations that saw
heavy rainfall on Friday. Lows tonight should be in the upper
60s to lower 70s.

The forecast area remains wedged between a trough centered to
our north and west and weak ridging associated with the Bermuda
high to our south and east. At the surface, a diffuse frontal
boundary remains in place and will continue to serve as a focal
point for convective development this afternoon and evening.
Scattered showers and thunderstorms are expected to develop and
could once again result in localized flash flooding and gusty
winds due to ample moisture in place with PWATs between 2 and
2.25 inches. This potential is echoed by both the SPC Day 1
Severe Weather Outlook and WPC Day 1 Excessive Rainfall Outlook
which place the entire CWA in a Marginal risk for severe weather
and heavy rainfall respectively. Morning low clouds should
transition to scattered cumulus by midday allowing temperatures
to reach the upper 80s to lower 90s, which is near to slightly
below normal values for mid-July. Convection should gradually
taper off tonight under partly cloudy skies with forecast low
temperatures in the lower 70s.

&&

.SHORT TERM /SUNDAY THROUGH MONDAY/...

Key Message(s):

-Stagnant pattern persists with a continued potential for heavy rainfall.

A frontal boundary will remain stalled across the Southeast
U.S. early next week. A weak upper level trough remains over the
mid Mississippi River Valley with disturbances moving through a
southwest flow aloft over The Midlands and CSRA. The lower
levels of the atmosphere remain exceptionally moist with
precipitable water levels in excess of two inches. The stalled
boundary as well as the sea breeze front will be the primary
triggers for diurnal convection with the weak upper level
disturbances enhancing the coverage. Locally heavy rainfall and
flash flooding remain the primary hazards as well as isolated
wet microbursts.

&&

.LONG TERM /MONDAY NIGHT THROUGH FRIDAY/...

Key Message(s):

-Subtle pattern change with a trend toward less rainfall and warmer
 temperatures.

There may be a subtle shift in an otherwise stagnant weather pattern
later next week. The ensembles as well as the deterministic medium
range models depict a retrogression of the weak upper level trough
and perhaps even the filling in of this feature. In addition the
Bermuda high builds westward into the Southeast U.S. This would
shift the highest chances of precipitation west of the Appalachians
and allow for warmer high temperatures. Will stick with a
persistence forecast until the model blend picks up on the subtle
pattern shift.

&&

.AVIATION /07Z SATURDAY THROUGH WEDNESDAY/...

IFR to LIFR ceilings are being observed at the Columbia and
Augusta terminals early this morning. While restrictions are not
ongoing at OGB, satellite data suggests the low clouds will
arrive there during the next hour or two. Low clouds are likely
to persist at the terminals this morning, gradually lifting and
transitioning to scattered cumulus decks by midday. In
addition, the terminals are being monitored for the possibility
of patchy fog though this should be a more transient threat
than the low ceilings. Scattered showers and thunderstorms are
expected to develop this afternoon and evening, likely
resulting in brief restrictions as they pass over the terminals.
Latest guidance suggests that low clouds may return Saturday
night as well, especially at AGS/DNL.

EXTENDED AVIATION OUTLOOK...Thunderstorms likely each day and
may cause brief restrictions. Abundant low level moisture may
cause early morning restrictions through mid-week.

&&

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

&&

$$