Alert archive / South Carolina / Flash Flood Warnings in 2012

Flash Flood Warning 9, NWS Charleston, SC

August 29, 2012Berkeley County, Charleston County, South Carolina

NWS Charleston, SC issued this flash flood warning at Aug 29, 2012, 7:05 PM EDT for Berkeley County, Charleston County, South Carolina. It was in force for 3 hr. 5 reports came from inside the area while it was in force.

The area

The outline as issued, with what was reported inside it.

The facts

Issued: Aug 29, 2012, 7:05 PM EDT (23:05 UTC)
Expired: Aug 29, 2012, 10:00 PM EDT
In force: 3 hr
Issued by: NWS Charleston, SC
Area: Storm-based polygon
Flood severity: None

Counties Berkeley County, SC, Charleston County, SC

The radar

The Charleston,SC radar (KCLX), 134 km from the middle of the area, began a volume at 23:05 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.

What was reported inside it

Time	Report	Where	Remark
Aug 29, 7:06 PM EDT	HEAVY RAIN 3.63	12 Ne Charleston, SC	MOUNT PLEASANT REGIONAL AIRPORT RECORDED 3.63 INCHES OF RAIN SINCE 615 PM.
Aug 29, 7:11 PM EDT	HEAVY RAIN 0	4 Nnw Capers Inlet, SC	4 TO 5 INCHES OF STANDING WATER ON HIGHWAT 17. THE ROAD IS STILL PASSABLE.
Aug 29, 7:36 PM EDT	FLASH FLOOD	2 Nne Boone Hall Planta, SC	POLICE HAD TO ASSIST A MOTORIST STRANDED IN HIGH WATER.
Aug 29, 7:49 PM EDT	HEAVY RAIN 5.1	12 Ne Charleston, SC	MOUNT PLEASANT REGIONAL AIRPORT HAS RECORDED 5.10 INCHES OF RAIN SINCE 615 PM.
Aug 29, 9:05 PM EDT	HEAVY RAIN 6.3	12 Ne Charleston, SC	6.30 INCHES OF RAIN HAS FALLEN SO FAR AT THE MOUNT PLEASANT REGIONAL AIRPORT.

Local storm reports filed while the alert was in force, from inside its polygon or its counties.

The nearest sounding before it

Charleston AFB, SC (KCHS), launched 12:00Z, 11.1 hours before the alert went out and 33 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: 1031 J/kg
Mixed-layer CIN: -43 J/kg
Mixed-layer LCL: 627 m above ground
0-6 km bulk shear: 17 kt
0-1 km storm-relative helicity: 19 m²/s²
0-3 km storm-relative helicity: 32 m²/s²
Significant tornado parameter: 0.0
Supercell composite: 0.6

Open this sounding in Storm Lab

The text

As transmitted, in the capitals the NWS used until 2016.

038 
WGUS52 KCHS 292305
FFWCHS
SCC015-019-300200-
/O.NEW.KCHS.FF.W.0009.120829T2305Z-120830T0200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/

BULLETIN - EAS ACTIVATION REQUESTED
FLASH FLOOD WARNING
NATIONAL WEATHER SERVICE CHARLESTON SC
705 PM EDT WED AUG 29 2012

THE NATIONAL WEATHER SERVICE IN CHARLESTON HAS ISSUED A

* FLASH FLOOD WARNING FOR...
  EXTREME SOUTH CENTRAL BERKELEY COUNTY IN SOUTHEAST SOUTH
  CAROLINA...
  CENTRAL CHARLESTON COUNTY IN SOUTHEAST SOUTH CAROLINA...

* UNTIL 1000 PM EDT

* AT 705 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED
  HEAVY RAIN OCCURRING ALONG A LINE EXTENDING FROM NAVAL WEAPONS 
  STATION CHARLESTON TO 13 MILES SOUTHWEST OF MCCLELLANVILLE. THE 
  AREA OF HEAVY RAIN WAS NEARLY STATIONARY.

  NEARLY 4 INCHES OF RAIN HAS FALLEN AS THE MOUNT PLEASANT REGIONAL
  AIRPORT SINCE 615 PM. AN ADDITIONAL 2 TO 3 INCHES COULD FALL
  OVER PARTS OF CENTRAL CHARLESTON COUNTY AND EXTREME SOUTH
  CENTRAL BERKELEY COUNTY THROUGH 10 PM. THE RISK FOR FLASH 
  FLOODING WILL INCREASE WITH HIGH TIDE IN PROGRESS.

* LOCATIONS IN THE ADVISORY INCLUDE BUT ARE NOT LIMITED TO...
  DUNES WEST...BERESFORD...PARK WEST...MOUNT PLEASANT REGIONAL
  AIRPORT...DANIEL ISLAND...BOONE HALL PLANTATION...HIGHWAY 17
  BETWEEN MOUNT PLEASANT AND AWENDAW...

PRECAUTIONARY/PREPAREDNESS ACTIONS...

AVOID DRIVING INTO WATER ON THE ROAD. THE WATER IS USUALLY DEEPER
THAN IT APPEARS AND THE ROAD MAY BE WASHED OUT. ONLY ONE FOOT OF
WATER WILL STALL A VEHICLE AND LESS THAN TWO FEET OF WATER CAN FLOAT
AND CARRY AWAY A VEHICLE. FLOODING IS THE NUMBER ONE WEATHER-RELATED
CAUSE OF DEATH IN THE UNITED STATES. WHEN ENCOUNTERING FLOODED ROADS
MAKE THE SMART CHOICE...TURN AROUND...DONT DROWN.

TO REPORT FLOODING...CONTACT THE NATIONAL WEATHER SERVICE IN
CHARLESTON TOLL FREE AT 1-888-383-2024.

&&

LAT...LON 3302 7954 3300 7957 3299 7954 3300 7957
      3295 7961 3294 7961 3294 7957 3297 7957
      3297 7955 3295 7957 3290 7957 3283 7969
      3284 7992 3298 7996 3304 7953

$$

1 follow-up statement

111 
WGUS72 KCHS 300201
FFSCHS

FLASH FLOOD STATEMENT
NATIONAL WEATHER SERVICE CHARLESTON SC
1001 PM EDT WED AUG 29 2012

SCC015-019-300209-
/O.EXP.KCHS.FF.W.0009.000000T0000Z-120830T0200Z/
/00000.0.ER.000000T0000Z.000000T0000Z.000000T0000Z.OO/
CHARLESTON SC-BERKELEY SC-
1001 PM EDT WED AUG 29 2012

...THE FLASH FLOOD WARNING WILL EXPIRE AT 1000 PM EDT FOR FOR EXTREME
SOUTH CENTRAL BERKELEY AND CENTRAL CHARLESTON COUNTIES...
...FLASH FLOOD WATCH IN EFFECT UNTIL 5 AM EDT THURSDAY...

THE HEAVIEST RAINS HAVE PUSHED OFFSHORE AND THE RISK FOR NEAR TERM
FLASH FLOODING HAS ENDED. RADAR SHOWS ADDITIONAL SHOWERS AND
THUNDERSTORMS BEGINNING TO REDEVELOP ACROSS SOUTHWEST CHARLESTON
COUNTY...WHICH MAY IMPACT AREAS BETWEEN MOUNT PLEASANT AND
AWENDAW LATER TONIGHT. A FLOOD WATCH REMAINS IN EFFECT UNTIL
5 AM THURSDAY. A FOOD WATCH MEANS THERE IS A POTENTIAL FOR
FLASH FLOODING.

ALTHOUGH THE SIGNIFICANT FLOODING HAS ENDED...DRAINAGE SYSTEMS AND
CULVERTS WILL REMAIN FULL. PONDING WATER WILL PERSIST IN LOW-LYING
AREAS AND MAY POSE A HAZARD TO MOTORISTS. STAY TUNED TO NOAA WEATHER
RADIO ALL-HAZARDS FOR THE LATEST WEATHER INFORMATION.

LAT...LON 3302 7954 3300 7957 3299 7954 3300 7957
      3295 7961 3294 7961 3294 7957 3297 7957
      3297 7955 3295 7957 3290 7957 3283 7969
      3284 7992 3298 7996 3304 7953

$$

The office that day

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

Issued	Product	Office	Counties	Lasted
Aug 29, 3:22 AM EDT	Flash Flood Watch	CHS		22 hr
Aug 29, 3:45 PM EDT	Special Weather Statement	CHS	Berkeley	30 min
Aug 29, 4:52 PM EDT	Areal Flood Advisory	CHS	Berkeley	83 min
Aug 29, 6:36 PM EDT	Areal Flood Advisory	CHS	Berkeley, Charleston	54 min
Aug 29, 6:52 PM EDT	Areal Flood Advisory	CHS	Berkeley, Charleston, Colleton, Dorchester	83 min
Aug 29, 7:45 PM EDT	Flash Flood Warning	CHS	Berkeley, Charleston, Colleton, Dorchester	3 hr
Aug 29, 7:58 PM EDT	Special Weather Statement	CHS	Allendale	32 min

Nearby

Flash Flood Warnings in South Carolina, 2012 Every flash flood warning in 2012

Sources

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