River Flood Warning 33, NWS Columbia, SC

Area Forecast Discussion
National Weather Service Columbia SC
413 PM EDT Tue Aug 6 2024

.SYNOPSIS...
Debby will continue slowly crossing the region through Thursday
night then begin moving away from the area. Confidence remains
high for potential heavy rainfall and flooding over the next
several days. Drier air should finally move into the region by
the weekend leading to lowering rain chances.

&&

.NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/...
Key Message(s):
- Heaviest rain bands should shift eastward overnight
  as Tropical Storm Debby moves offshore.
- Flash flood risks will continue, especially east of I-77 and
  south of I-20.

Tropical Storm Debby moves offshore this afternoon through tonight.
This movement should result in the heaviest precipitation shifting
closer to the coast overnight. Areas west of I-77 and north of
I-20 should benefit from the decreased chance of precipitation
and lesser rainfall accumulations as the night progresses, while
areas east of I-77 and south of I-20 should see a continuation
of showers and isolated thunderstorms albeit with somewhat less
intense rainfall rates. Any additional rainfall will exacerbate
ongoing flash flooding, especially for the lower CSRA and
eastern Midlands.

Rainfall accumulations through tonight should range from less than
one quarter of inch in the Upper CSRA to three to six inches in the
eastern Midlands with the sharpest gradient just north of the I-20
corridor.

&&

.SHORT TERM /6 AM WEDNESDAY MORNING THROUGH THURSDAY NIGHT/...
Key Message(s):

- An additional round of heavy rain is expected Wednesday Night
  into Thursday which may cause additional flooding
- Potential for life threatening flash flooding continues
  Wednesday through Thursday
- A Flood Watch is in effect through Thursday evening

Updates: The most significant impact is still expected to be
flooding potential. Although there may be a brief period on
Wednesday without heavy rainfall, we expect to see deep moisture
advection and heavy rain return to the region Wednesday night
and Thursday as Debby shifts W. This has led to an increased
risk of flooding further west into the northern Midlands and
Catawba regions.

Forecast and Impacts: As Debby first shifts eastward early in
the short term, western portions of the area may see a bit of
lull early Wednesday. Some western portions north of I-20 may
not get much rainfall with only the eastern areas near I-95
still seeing moderate or heavy rain.

As Debby shifts north and west, widespread heavy rainfall
across much of the area becomes more likely on Wednesday night
and Thursday with life threatening flash flooding possible in
portions of the Midlands. The combination of deep tropical
moisture of PWAT values over 2.5" and an extremely slow moving
system should yield rainfall totals of generally 4 to 8 inches
over central SC with locally higher amounts. It appears that
the heaviest precip will likely fall Wednesday night and into
Thursday afternoon. WPC has continued their high risk for the
Catawba and Pee Dee regions. It be should be noted the rarity of
such a situation with portions of our in area in Moderate and
High Risks for three consecutive days.

While flash flooding remains the main concern, additional
hazards are possible based on the intensity and track of Debby
as it nears the area. ECMWF shows a 50 to 60 kt swath of winds
at 925mb entering the Pee Dee region Wednesday night into
Thursday morning. Other deterministic models have varying
speeds and timing hampering confidence but the potential for
tropical storm wind gusts exists. There is also potential for a
tornado threat across the eastern and half of the forecast area
but again this will depend on the track.

&&

.LONG TERM /FRIDAY THROUGH TUESDAY/...
Key Message(s):

- Drier air moves into the region in the long term but river
  flooding will remain an issue in the eastern Midlands.

Drier air with PWAT's below average will wrap in behind Debby
in the first portion of the long term. The exact timing is
still somewhat unclear as to when exactly Debby will accelerate
north but there is consensus that the weekend should be limited
to just a slight chance of rain. The remainder of the long term
is fairly calm and near average weather expected as we move
into next week.

&&

.AVIATION /20Z TUESDAY THROUGH SUNDAY/...
Restrictions expected to dominate the period

IFR conditions will persist at all TAF sites through 07/04Z due to
Debby associated rain bands. Visibilities should improve after
07/04Z at all TAF sites besides OGB as Tropical Storm Debby moves
offshore and the heaviest rain bands move closer to the South
Carolina coast. Ceilings should raise a bit, however they will
persist due to the abundant tropical moisture across the region.

EXTENDED AVIATION OUTLOOK...Low ceilings, reduced visibility and
rain, heavy at times, are expected to continue through at least
Thursday. Gusty winds may be possible through Wednesday night
as Debby moves through the region.

&&

.CAE WATCHES/WARNINGS/ADVISORIES...
SC...Flood Watch through Friday morning for SCZ016-021-022-027>031-
     035-037-038-041-115-116-135>137.
GA...Flood Watch through Friday morning for GAZ063>065-077.

&&

Preliminary Local Storm Report
National Weather Service Columbia SC
1232 PM EDT Tue Aug 6 2024

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

1050 AM     Flash Flood      1 WSW Orangeburg        33.49N 80.88W
08/06/2024                   Orangeburg         SC   Local Official

            City of Orangeburg has closed portions of
            Riverside Drive due to flash flooding.

&&

BC

Preliminary Local Storm Report
National Weather Service Columbia SC
206 PM EDT Tue Aug 6 2024

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0142 PM     Flash Flood      1 ENE Santee            33.49N 80.47W
08/06/2024                   Orangeburg         SC   Dept of Highways

            SCDPS reported that Bradford Blvd is washed
            out near Hwy 6.

&&

BC

Preliminary Local Storm Report
National Weather Service Columbia SC
310 PM EDT Tue Aug 6 2024

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0107 PM     Flash Flood      6 WSW Munnerlyn         32.94N 82.07W
08/06/2024                   Burke              GA   Emergency Mngr

            Burke County reported Herndon Rd was closed
            with water running over roadway 2 miles
            north of Byne Sunshine Rd.

&&

BC

Preliminary Local Storm Report
National Weather Service Columbia SC
429 PM EDT Tue Aug 6 2024

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0329 PM     Flash Flood      Wilkinson Heights       33.49N 80.84W
08/06/2024                   Orangeburg         SC   Law Enforcement

            A SCHP Trooper reported flooded intersection
            at John C Calhoun Dr and Sprinkle Ave.

&&

BC

Preliminary Local Storm Report
National Weather Service Columbia SC
434 PM EDT Tue Aug 6 2024

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0320 PM     Flash Flood      Orangeburg              33.49N 80.87W
08/06/2024                   Orangeburg         SC   Broadcast Media

            Reporter reported abandoned homes along
            Waring St are being flooded via social
            media; pictures included.

&&

BC

Preliminary Local Storm Report
National Weather Service Columbia SC
612 PM EDT Tue Aug 6 2024

..TIME...   ...EVENT...      ...CITY LOCATION...     ...LAT.LON...
..DATE...   ....MAG....      ..COUNTY LOCATION..ST.. ...SOURCE....
            ..REMARKS..

0520 PM     Flash Flood      3 WNW Lakewood          33.86N 80.40W
08/06/2024                   Sumter             SC   911 Call Center

            Sumter County Dispatch reported 6 inches of
            water flowing across Cains Mill Rd near
            Nasty Branch.

0514 PM     Flash Flood      2 SW McEntire JNGB      33.90N 80.83W
08/06/2024                   Richland           SC   Law Enforcement

            SCHP reported flooding along Cabin Creek Rd
            at Gillwood Rd.

&&

CRL