Alert archive / South Carolina / Flash Flood Warnings in 2018

Flash Flood Warning 4, NWS Columbia, SC

July 23, 2018Kershaw County, Richland County, South Carolina

NWS Columbia, SC issued this flash flood warning at Jul 23, 2018, 12:51 PM EDT for Kershaw County, Richland County, South Carolina. It was in force for 114 min. No storm report in the archive falls inside the area while it was in force.

The area

The outline as issued.

The facts

Issued: Jul 23, 2018, 12:51 PM EDT (16:51 UTC)
Expired: Jul 23, 2018, 2:45 PM EDT
In force: 114 min
Issued by: NWS Columbia, SC
Area: Storm-based polygon
Flood severity: None

Counties Kershaw County, SC, Richland County, SC

The radar

The Columbia radar (KCAE), 25 km from the middle of the area, began a volume at 16:54 UTC, the scan nearest the moment this went out.

Open the radar archive at this moment

The archived warnings, watches and discussions in force at that minute are drawn over the scan, this one among them.

Did it verify

Not verified. The Iowa Environmental Mesonet's Cow found no qualifying storm report inside this flash flood warning while it was in force. That is not proof nothing happened: reports are thin where few people live.

Cow counts a report within 15 km of the polygon while the warning was in force: a tornado for a tornado warning; hail of 1 inch or more, a gust of 58 mph or more or wind damage for a severe thunderstorm warning; a flash flood report for a flash flood warning.

The nearest sounding before it

Charleston AFB, SC (KCHS), launched 12:00Z, 4.9 hours before the alert went out and 141 km from the middle of its area. This is the routine balloon launch nearest before it, the air the forecaster had in hand, not a measurement taken for the alert.

Skew-T log-p

Temperature in red, dew point in green, the mixed-layer parcel dashed.

Hodograph

The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km.

Mixed-layer CAPE: 1386 J/kg
Mixed-layer CIN: -18 J/kg
Mixed-layer LCL: 751 m above ground
0-6 km bulk shear: 21 kt
0-1 km storm-relative helicity: 52 m²/s²
0-3 km storm-relative helicity: 102 m²/s²
Significant tornado parameter: 0.3
Supercell composite: 2.1

Open this sounding in Storm Lab

The text

As transmitted.

063 
WGUS52 KCAE 231651
FFWCAE
SCC055-079-231845-
/O.NEW.KCAE.FF.W.0004.180723T1651Z-180723T1845Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
Flash Flood Warning
National Weather Service Columbia SC
1251 PM EDT MON JUL 23 2018

The National Weather Service in Columbia has issued a

* Flash Flood Warning for...
  Southwestern Kershaw County in central South Carolina...
  Eastern Richland County in central South Carolina...

* Until 245 PM EDT.

* At 1250 PM EDT, Doppler radar and automated rain gauges indicated
  thunderstorms producing heavy rain across the warned area. Up to
  two inches of rain have already fallen. Flash flooding is expected
  to begin shortly.

* Some locations that will experience flooding include...
  Forest Acres, Dentsville, Woodfields, Arcadia Lakes, Woodfield and
  Fort Jackson.

Additional rainfall amounts of two inches are possible in the warned 
area.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Most flooding deaths occur in vehicles. Never drive through a flooded
roadway or around barricades. Turn around, don't drown.

Report any flooding directly to the Columbia National Weather Service
at 803 234 4115 when it is safe to do so. You can also send reports
by Facebook or Twitter to NWSColumbia or by e-mail at
NWS.Columbia@noaa.gov.

&&

LAT...LON 3382 8074 3385 8099 3386 8100 3417 8095
      3416 8067

$$

What forecasters said that day

The local office's own words before this flash flood warning went out, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.

NWS Columbia, SC wrote its last area forecast discussion before this flash flood warning went out at Jul 23, 10:35 AM EDT, 2 hours 16 minutes earlier.

Area forecast discussion, Jul 23, 10:35 AM EDT, 2 hours 16 minutes before

Area Forecast Discussion
National Weather Service Columbia SC
1035 AM EDT Mon Jul 23 2018

.SYNOPSIS...
A deep upper trough will remain over the E CONUS through late
next week. This will result in increasing moisture and chances
of showers and thunderstorms through next weekend.

&&

.NEAR TERM /UNTIL 6 PM THIS EVENING/...

Elongated upper low stretched from the Ohio Valley southward to
the northeastern Gulf Coast is sandwiched between a large ridges
over the desert southwest and northern Atlantic. The trough
axis is just west of the forecast area with southerly upper
level flow over the region. Accas clouds this morning indicate
an unstable atmosphere and current CAE WSR-88D imagery shows a
few showers around the area. With the forecast area under deep
southerly flow today increasing pwat values increasing to over
1.75 inches by this afternoon and short waves rotating through
the base of the trough expect scattered to numerous showers and
thunderstorms through the afternoon and into the evening. Lapse
rates will remain weak and best wind shear will remain to our
north and east so severe thunderstorms are not favored but
isolated strong storms cannot be ruled out. Heavy rain due to
slow moving or training convection is the more concerning threat
today. Afternoon high temperatures will be in the upper 80s to
lower 90s.

&&

.SHORT TERM /6 PM THIS EVENING THROUGH WEDNESDAY NIGHT/...
The upper level trough just west of the CWA will support
ongoing showers and thunderstorms into the evening. Moderate
elevated instability and PWAT values around 2.0 inches indicate
heavy rain and localized flooding will continue to be a threat
overnight. The highest coverage may be over the CSRA where
moisture will be higher and upper-level shear vorticity
strongest.

The upper trough will remain over the Southeast through
Wednesday with surface low pressure in the Deep South. This
setup will direct moist, southerly flow into the forecast area.
PWAT values will be around 2.0 to 2.25 inches across much of
the Midlands and CSRA. Synoptic scale accent and abundant
moisture is expected to result in widespread showers and
thunderstorms, with the greatest coverage in the afternoon
around the time of peak heating. There is a marginal risk of
localized flooding during the period due to the large amount of
atmospheric moisture and moderate potential instability. Highs
will be in the upper 80s to around 90 degrees with overnight
lows in the low to mid 70s.

&&

.LONG TERM /THURSDAY THROUGH SUNDAY/...
On Thursday the models suggest the upper-level low will weaken
as mid-level ridging returns over the Southeast. This setup
supports a more climatological pattern of scattered, diurnal
convection and warming temperatures. A broad upper-level trough
will then move into the Great Lakes region with the associated
cold front sagging into the mid-Atlantic and stalling. At this
time it appears the front will remain north of the area.
Although it may serve as a focus for showers and thunderstorms
which propagate into the FA, increasing the chance for rainfall
near the end of the long term. Temperatures will be near or
slightly above normal through the period.

&&

.AVIATION /13Z MONDAY THROUGH FRIDAY/...
VFR conditions for most of the TAF period with showers and
thunderstorms possible through the period.

Upper level trough axis just west of the area will keep deep
southerly flow over the region through the period. With diurnal
heating and disturbances rotating through the base of the trough
expect increasing chances of showers and thunderstorms through
the afternoon and evening hours. Currently a few showers just
west of OGB with satellite imagery showing cumulus quickly
developing across the region. Main concern with thunderstorms
will be strong and gusty winds along with locally heavy
rainfall. With low confidence in have remained with VCSH for all
terminals and will adjust as confidence increases.

EXTENDED AVIATION OUTLOOK...Increasing confidence in scattered
to numerous mainly afternoon and evening thunderstorms each day
along with late night/early morning fog/stratus possible.

&&

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

&&

S

Hazardous weather outlook, Jul 23, 3:59 AM EDT, 8 hours 52 minutes before

Hazardous Weather Outlook
National Weather Service Columbia SC
359 AM EDT Mon Jul 23 2018

GAZ040-063>065-077-SCZ015-016-018-020>022-025>031-035>038-041-240800-
Lincoln-McDuffie-Columbia-Richmond-Burke-Lancaster-Chesterfield-
McCormick-Newberry-Fairfield-Kershaw-Edgefield-Saluda-Lexington-
Richland-Lee-Aiken-Sumter-Barnwell-Orangeburg-Calhoun-Clarendon-
Bamberg-
359 AM EDT Mon Jul 23 2018

This Hazardous Weather Outlook is for the Midlands of South Carolina
and the Central Savannah River area of Georgia.

.DAY ONE...Today and Tonight.

Heavy rain and localized flooding are possible this afternoon and
evening. Cannot rule out a few strong or severe thunderstorms as well.

.DAYS TWO THROUGH SEVEN...Tuesday through Sunday.

Heavy rain and localized flooding are possible Tuesday and Wednesday.

.SPOTTER INFORMATION STATEMENT...

Spotter activation is not expected at this time.

In the hours before

Special weather statement, Jul 23, 8:14 AM EDT, 4 hours 37 minutes before

Special Weather Statement
National Weather Service Columbia SC
814 AM EDT MON JUL 23 2018

SCZ021-028-231300-
Fairfield SC-Richland SC-
814 AM EDT MON JUL 23 2018

...Strong Thunderstorms Will Impact Portions of Fairfield and
northwestern Richland Counties Until 900 AM EDT....

At 813 AM EDT...National Weather Service doppler radar indicated a
strong thunderstorm 10 miles north of Irmo, moving north at 25 mph.

  HAZARD...gusty winds 40 to 50 mph, pea sized hail and localized
           minor flooding.

  IMPACT...expect minor damage to tree limbs and blowing around of
           light, unsecured objects. Minor hail damage to plants,
           trees and crop is possible. Damage to windshields is
           unlikely. Localized, minor flooding of low lying and poor
           drainage areas is also possible.

Some locations in the path of this storm include...
Columbia, Irmo, Winnsboro, Winnsboro Mills and Lake Murray Of
Richland.

Heavy rainfall is occurring with this storm, and may cause localized
flooding. Do not drive your vehicle through flooded roadways.

This includes the following highways...
 Interstate 26 between mile markers 93 and 102.
 Interstate 77 between mile markers 36 and 49.

LAT...LON 3452 8089 3408 8115 3410 8120 3410 8123
      3416 8131 3417 8130 3420 8134 3424 8132
      3427 8134 3430 8134 3431 8136 3438 8139
      3456 8142
TIME...MOT...LOC 1213Z 196DEG 23KT 3425 8122

Local storm report, Jul 23, 8:19 AM EDT, 4 hours 32 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE COLUMBIA SC
819 AM EDT MON JUL 23 2018

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

0805 AM     HAIL             1 W IRMO                34.09N 81.21W
07/23/2018  E0.25 INCH       LEXINGTON          SC   PUBLIC

            REPORT OF PEA SIZE HAIL AND ESTIMATED WIND
            GUSTS UP TO 40 MPH NEAR IRMO.

&&

LCV

Local storm report, Jul 23, 8:21 AM EDT, 4 hours 30 minutes before

PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE COLUMBIA SC
821 AM EDT MON JUL 23 2018

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

0811 AM     HAIL             2 N IRMO                34.13N 81.19W
07/23/2018  E0.25 INCH       RICHLAND           SC   EMERGENCY MNGR

            REPORTED PEA SIZE HAIL IN THE VICINITY OF
            KOON ROAD AND COOGLER ROAD NORTH OF IRMO.

&&

LCV

Special weather statement, Jul 23, 12:05 PM EDT, 46 minutes before

Special Weather Statement
National Weather Service Columbia SC
1205 PM EDT MON JUL 23 2018

SCZ022-028-231645-
Kershaw SC-Richland SC-
1205 PM EDT MON JUL 23 2018

...Strong Thunderstorms Will Impact Portions of southwestern Kershaw
and southeastern Richland Counties Until 1245 PM EDT....

At 1205 PM EDT...National Weather Service doppler radar indicated a
strong thunderstorm 7 miles south of Fort Jackson, or 8 miles
southeast of Forest Acres, moving north at 10 mph.

  HAZARD...gusty winds 40 to 50 mph and pea sized hail.

  IMPACT...expect minor damage to tree limbs and blowing around of
           light, unsecured objects. Minor hail damage to plants,
           trees and crops is possible. Damage to windshields is
           unlikely.

Some locations in the path of this storm include...
Columbia, Forest Acres, Dentsville, Woodfields, Arcadia Lakes,
Woodfield and Fort Jackson.

This includes the following highways...
 Interstate 20 in South Carolina between mile markers 72 and 88.
 Interstate 77 between mile markers 5 and 21.

LAT...LON 3396 8069 3378 8081 3380 8087 3381 8087
      3381 8089 3382 8092 3383 8091 3382 8094
      3384 8095 3385 8099 3388 8101 3414 8099
      3416 8064
TIME...MOT...LOC 1605Z 192DEG 8KT 3392 8088

LCV

Special weather statement, Jul 23, 12:21 PM EDT, 30 minutes before

Special Weather Statement
National Weather Service Columbia SC
1221 PM EDT MON JUL 23 2018

SCZ020-027-231645-
Lexington SC-Newberry SC-
1221 PM EDT MON JUL 23 2018

...Strong Thunderstorms Will Impact Portions of northwestern
Lexington and southeastern Newberry Counties Until 1245 PM EDT....

...Boaters on Lake Murray Should Seek Safe Harbor...

At 1220 PM EDT...National Weather Service doppler radar indicated a
strong thunderstorm 8 miles west of Lexington, moving north at 25
mph.

  HAZARD...gusty winds 40 to 50 mph and pea sized hail.

  IMPACT...expect minor damage to tree limbs and blowing around of
           light, unsecured objects. Minor hail damage to plants,
           trees and crops is possible. Damage to windshields is
           unlikely.

Some locations in the path of this storm include...
Lexington, Red Bank, Prosperity, Chapin, Gilbert, Summit, Little
Mountain, Peak and Lake Murray Of Richland.

PRECAUTIONARY/PREPAREDNESS ACTIONS...

Boaters on Lake Murray should move to shore and seek shelter. Strong,
erratic wind gusts and lightning are possible. If you can hear
thunder, you are close enough to be struck by lightning.

Persons in campgrounds should seek shelter until this storm passes.

&&

This includes the following highways...
 Interstate 20 in South Carolina between mile markers 45 and 52.
 Interstate 26 between mile markers 85 and 92.

LAT...LON 3420 8134 3417 8130 3415 8131 3413 8131
      3410 8127 3410 8126 3389 8126 3387 8143
      3402 8150 3407 8147 3407 8150 3409 8153
      3419 8158 3424 8132
TIME...MOT...LOC 1620Z 165DEG 21KT 3398 8138

LCV

The office that day

Everything else NWS Columbia, SC issued on the same UTC day.

Issued	Product	Office	Counties	Lasted
Jul 23, 8:14 AM EDT	Special Weather Statement	CAE	Fairfield	46 min
Jul 23, 12:05 PM EDT	Special Weather Statement	CAE	Richland	40 min
Jul 23, 12:21 PM EDT	Special Weather Statement	CAE	Lexington	24 min
Jul 23, 12:29 PM EDT	Severe Thunderstorm Warning	CAE	Kershaw, Richland	46 min
Jul 23, 12:31 PM EDT	Areal Flood Advisory	CAE	Richland	3 hr
Jul 23, 1:05 PM EDT	Severe Thunderstorm Warning	CAE	Lexington	40 min
Jul 23, 1:52 PM EDT	Flash Flood Warning	CAE	Lexington, Richland	113 min
Jul 23, 1:52 PM EDT	Severe Thunderstorm Warning	CAE	Richland, Sumter	38 min
Jul 23, 2:47 PM EDT	Areal Flood Advisory	CAE	Richland, Sumter	118 min
Jul 23, 3:14 PM EDT	Severe Thunderstorm Warning	CAE	Calhoun, Clarendon, Sumter	46 min
Jul 23, 4:13 PM EDT	Areal Flood Advisory	CAE	Calhoun, Sumter	2 hr
Jul 23, 4:33 PM EDT	Tornado Warning	CAE	Clarendon, Sumter	27 min
Jul 23, 5:11 PM EDT	Special Weather Statement	CAE	Chesterfield	34 min
Jul 23, 5:21 PM EDT	Tornado Warning	CAE	Lee	9 min
Jul 23, 5:48 PM EDT	Areal Flood Advisory	CAE	Chesterfield	117 min
Jul 23, 6:02 PM EDT	Areal Flood Advisory	CAE	Aiken, Barnwell	118 min
Jul 23, 6:18 PM EDT	Special Weather Statement	CAE	Barnwell	42 min
Jul 23, 6:32 PM EDT	Severe Thunderstorm Warning	CAE	Aiken, Barnwell	43 min
Jul 23, 7:05 PM EDT	Areal Flood Advisory	CAE	Lexington	115 min

Nearby

Flash Flood Warnings in South Carolina, 2018 Every flash flood warning in 2018

Sources

The product and its follow-ups from the Iowa Environmental Mesonet's archive of National Weather Service and Storm Prediction Center text; the sounding from the Mesonet's radiosonde archive; radar from the NEXRAD Level II archive.