A line of thunderstorms developed late in the day and produced very heavy rainfall across much of the Downtown Charleston area. The rain fell in an area that had already seen extremely heavy rainfall amounts from the previous day.
Every event with a place to put it. Tap one for its entry below.
Deaths and injuries are direct and indirect together, as the offices filed them. Damage is property and crops in the dollars of the year, not adjusted for inflation, and only where an office estimated it.
The episode as NWS CHS wrote it up.
A line of thunderstorms developed late in the day and produced very heavy rainfall across much of the Downtown Charleston area. The rain fell in an area that had already seen extremely heavy rainfall amounts from the previous day. Flash flooding occurred in similar areas with many roads closed. Other thunderstorms developed into the evening and produced flash flooding further inland in Allendale.
The local office's own words before the first event, as it sent them, from the Iowa Environmental Mesonet's archive of National Weather Service text.
NWS Charleston, SC wrote its last area forecast discussion before the first event at Aug 29, 5:01 PM EST, 1 hour 35 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON SC 601 PM EDT WED AUG 29 2012 .SYNOPSIS... DEEP TROPICAL MOISTURE WILL REMAIN IN PLACE ACROSS THE AREA THROUGH THURSDAY BRINGING HIGHER THAN NORMAL RAIN CHANCES. A WEAK COLD FRONT WILL PUSH THROUGH THE AREA FROM NORTH TO SOUTH LATE THURSDAY AND THURSDAY NIGHT. WEAK HIGH PRESSURE WILL THEN SETTLE OVER THE AREA FRIDAY AND SATURDAY...BEFORE A TROUGH OF LOW PRESSURE APPROACHES FROM THE WEST LATE WEEKEND INTO EARLY NEXT WEEK. && .NEAR TERM /UNTIL 6 AM THURSDAY MORNING/... UPDATED GRIDS/TEXT PRODUCTS TO TAKE CURRENT MESOSCALE TRENDS INTO ACCOUNT. TWO AREAS OF CONCERN. 1. OUTFLOW MOVING SOUTH OUT OF ORANGEBURG COUNTIES IS POISED TO INTERSECT THE SEA BREEZE SHORTLY. THE ATMOSPHERE IS QUITE MOIST AND UNSTABLE ACROSS THE CHARLESTON TRI-COUNTY AREA WHICH WILL LIKELY SUPPORT ADDITIONAL CONVECTIVE DEVELOPMENT AS LOW-LEVEL CONVERGENCE MAXIMIZES. LOW/MID-LEVEL FLOW OFF KCLX VWP SUGGESTS ANY DEEP CONVECTIVE CELLS THAT DEVELOP ALONG THE INTERSECTION WILL MOVE EAST...POSSIBLY IMPACTING AREAS THAT SAW 4-8 INCHES OF RAIN YESTERDAY INCLUDING DOWNTOWN CHARLESTON. COMPLICATING MATTERS IS HIGH TIDE IS QUICKLY APPROACHING. THERE WILL CERTAINLY BE A POTENTIAL FOR TRAINING AND WITH PWATS IN EXCESS OF 2.25 INCHES... IT WILL NOT TAKE LONG FOR RAIN TO CAUSE FLOODING PROBLEMS ACROSS THE CHARLESTON METRO AREA. THE FLASH FLOOD WATCH REMAINS IN EFFECT FOR TIDAL BERKELEY AND CHARLESTON COUNTIES UNTIL 11 PM. INCREASED POPS TO 70 PERCENT ACROSS NORTHERN HALF OF FORECAST AREA THROUGH MID- EVENING. 2. CONVECTION MOVING QUICKLY NORTH FROM FAR SOUTHEAST GEORGIA IS POISED TO CROSS THE ALTAMAHA RIVER. INCREASED POPS TO 80 PERCENT FOR AREAS ROUGHLY SOUTH OF A CLAXTON-RICHMOND HILL LINE IT DOES APPEAR MEASURABLE RAINFALL IS A GOOD BET FOR MANY OF THESE AREAS. LOCALLY HEAVY RAINFALL WILL ALSO BE POSSIBLE...BUT THIS AREA CAN TAKE A BIT MORE IN THE WAY OF RAIN PER LATEST FLASH FLOOD GUIDANCE. && .SHORT TERM /6 AM THURSDAY MORNING THROUGH SATURDAY/... ONE MORE DAY OF DEEP TROPICAL MOISTURE IS IN STORE FOR THURSDAY...SUPPORTING SCATTERED AFTERNOON THUNDERSTORMS WITH LOCALLY HEAVY RAIN. THE BEST CHANCE WILL GENERALLY BE SOUTH AND WEST OF THE SAVANNAH RIVER...WITH DRYING SLOWLY WORKING INTO THE SOUTH CAROLINA COUNTIES LATE IN THE DAY. PLENTIFUL CLOUD COVER WILL KEEP MAX TEMPS IN THE MID 80S. THURSDAY NIGHT A WEAK BACKDOOR COLD FRONT WILL PUSH IN FROM THE NORTH AND MOVE THROUGH RATHER QUICKLY...BRINGING IN DRIER AIR. FRIDAY WILL BE MUCH SUNNIER...AND HENCE WARMER EVEN THOUGH THE AREA WILL BE BEHIND A COLD FRONT. THERE WILL STILL BE A SLIGHT CHANCE OF AFTERNOON THUNDERSTORMS...MAINLY WEST OF INTERSTATE 95...BUT THE COVERAGE WILL BE LOWER THAN THE PAST COUPLE OF DAYS. GFS HOLDS ON TO DEEPER MOISTURE OVER INTERIOR GEORGIA...BUT FOR NOW I PREFER THE DRIER SOLUTION OF THE NAM12 BASED ON THE 50S DEW POINTS BEHIND THE FRONT IN VIRGINIA TODAY. OUR DEW POINTS CERTAINLY WONT GET THAT LOW...BUT IT INDICATES THE AIR IS REASONABLY DRY FOR LATE AUGUST. MOSTLY SUNNY WEATHER WILL CONTINUE INTO SATURDAY...AND TEMPS MAY EVEN BE A DEGREE OR TWO WARMER AS HEIGHTS BUILD A BIT ALOFT. && .LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/... AFTER A RAIN-FREE NIGHT SATURDAY NIGHT...HIGH PRESSURE AT THE SURFACE AND ALOFT WILL WEAKEN/RETREAT OFFSHORE...ALLOWING A TROUGH OF LOW PRESSURE AT THE SURFACE/ALOFT AND ASSOCIATED DEEP LAYER MOISTURE TO DEVELOP OVER THE SOUTHEAST. WHILE GUIDANCE DIFFERS CONCERNING DETAILS OF THE TROUGH DEPTH/POSITION AND THE MAGNITUDE/EXPANSE OF THE ASSOCIATED PLUME OF MOISTURE...OVERALL TRENDS POINT TOWARD INCREASING POPS SUNDAY THROUGH THE MIDDLE OF NEXT WEEK. TEMPERATURES SHOULD AVERAGE CLOSE TO NORMAL BUT WILL DEPEND GREATLY ON CLOUD COVER/PRECIPITATION. && .AVIATION /22Z WEDNESDAY THROUGH MONDAY/... MVFR CIGS/VSBYS ARE POSSIBLE THIS EVENING AT BOTH TERMINALS WITH SHOWERS AND/OR THUNDERSTORMS WHILE DEEP MOISTURE REMAINS OVER THE AREA...MAINLY THROUGH 00Z. SHOWERS AND/OR THUNDERSTORMS SHOULD WANE AFTER DARK. LOW LEVEL MOISTURE WILL AGAIN PROVIDE CONDITIONS FAVORABLE FOR SUB-VFR CONDITIONS BETWEEN 09Z-14Z THURSDAY...BUT CONFIDENCE IN STARTING TIME AND DURATION IS TOO LOW TO JUSTIFY PREVAILING SUB-VFR CONDITIONS AT THIS TIME. EXTENDED AVIATION OUTLOOK...THURSDAY THE TERMINALS WILL STILL BE SUSCEPTIBLE TO SOME MVFR CIGS...ESPECIALLY SAV...IN THE DEEP MOISTURE. THERE COULD ALSO BE REDUCED CIGS/VSBYS IN THUNDERSTORMS THURSDAY AFTERNOON. CONDITIONS SHOULD IMPROVE SIGNIFICANTLY FRIDAY INTO THE WEEKEND WITH A BUBBLE OF HIGH PRESSURE SETTING UP OVER THE AREA. ONLY ISOLATED THUNDERSTORMS ARE EXPECTED THIS WEEKEND. && .MARINE... TONIGHT...WINDS/SEAS WILL REMAIN WELL BELOW SMALL CRAFT ADVISORY THRESHOLDS WITH A WEAK PRESSURE GRADIENT OVER THE COASTAL WATERS. IN GENERAL WINDS WILL REMAIN BETWEEN 5-10 KNOTS WITH THE EXCEPTION OF OCCASIONAL 15 KNOT WINDS BEYOND 20 NM. SEAS BETWEEN 2-4 FEET WILL GRADUALLY SUBSIDE OVERNIGHT. WINDS WILL BE LESS THAN 15 KNOTS AWAY FROM CONVECTION THURSDAY THROUGH SUNDAY WITH SEAS MAINLY 2 FEET IN THE NEARSHORE WATERS AND 2 OR 3 FEET IN THE OFFSHORE GEORGIA WATERS. WINDS AND SEAS MAY PICK UP A TOUCH SUNDAY NIGHT AND MONDAY AS THE PRESSURE GRADIENT TIGHTENS UP...BUT CONDITIONS SHOULD STILL BE WELL BELOW SCA CRITERIA. RIP CURRENTS...DUE TO THE AFFECTS OF THE APPROACHING FULL MOON...LINGERING SWELL ENERGY...AND LIGHT ONSHORE FLOW...A MODERATE RISK OF RIP CURRENTS WILL CONTINUE UNTIL THIS EVENING. && .TIDES/COASTAL FLOODING... MODELS SUGGEST POSITIVE TIDAL ANOMALIES OF UP TO ONE HALF FOOT THROUGH MID-LATE WEEK AND THIS COULD LEAD TO SHALLOW SALTWATER FLOODING DURING THE TIME OF THE EVENING HIGH TIDES. THE SITUATION COULD BECOME ENHANCED IF HEAVY RAINFALL OCCURS DURING THE HIGH TIDE...ESPECIALLY IN THE NORMALLY FLOOD-PRONE AREAS SUCH AS DOWNTOWN CHARLESTON AND SAVANNAH. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...NONE. SC...FLASH FLOOD WATCH UNTIL 11 PM EDT THIS EVENING FOR SCZ050-052. MARINE...NONE. && SYNOPSIS... NEAR TERM... SHORT TERM...ALSHEIMER LONG TERM...ALSHEIMER AVIATION...ALSHEIMER/DPB MARINE...ALSHEIMER/DPB TIDES/COASTAL FLOODING...
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE CHARLESTON SC 315 PM EDT WED AUG 29 2012 SCZ050-301915- CHARLESTON- 315 PM EDT WED AUG 29 2012 ...FLASH FLOOD WATCH IN EFFECT UNTIL 11 PM EDT THIS EVENING... ...MODERATE RISK FOR RIP CURRENTS IN EFFECT UNTIL 8 PM EDT THIS EVENING... THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTHEAST SOUTH CAROLINA. .DAY ONE...THIS AFTERNOON AND TONIGHT. PLEASE LISTEN TO NOAA WEATHER RADIO OR GO TO WEATHER.GOV ON THE INTERNET FOR MORE INFORMATION ABOUT THE FOLLOWING HAZARDS. FLASH FLOOD WATCH. MODERATE RISK FOR RIP CURRENTS. COASTAL HAZARDS...REGARDLESS OF WHETHER RAIN IS FALLING...AN ELEVATED HIGH TIDE COULD PRODUCE SHALLOW SALT WATER FLOODING THIS EVENING. A COASTAL FLOOD ADVISORY COULD EVENTUALLY BE REQUIRED. .DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY. FLOODING...LOCALLY HEAVY RAINFALL AND LOCALIZED FLOODING COULD OCCUR THURSDAY... ESPECIALLY IN LOCATIONS IN AND AROUND WEST ASHLEY...DOWNTOWN CHARLESTON...NORTH CHARLESTON AND MOUNT PLEASANT. COASTAL HAZARDS...ELEVATED TIDES WILL CONTINUE AND COULD PRODUCE SHALLOW SALT WATER FLOODING AROUND THE TIMES OF HIGH TIDE EACH EVENING THROUGH LATE WEEK. .SPOTTER INFORMATION STATEMENT... SPOTTER ASSISTANCE IS NOT ANTICIPATED AT THIS TIME. GAZ087-088-099>101-114>116-118-137-138-140-SCZ040-042>045-047-301915- JENKINS-SCREVEN-CANDLER-BULLOCH-EFFINGHAM-TATTNALL-EVANS- INLAND BRYAN-INLAND CHATHAM-LONG-INLAND LIBERTY-INLAND MCINTOSH- ALLENDALE-HAMPTON-INLAND COLLETON-DORCHESTER-INLAND BERKELEY- INLAND JASPER- 315 PM EDT WED AUG 29 2012 THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTHEAST GEORGIA AND SOUTHEAST SOUTH CAROLINA. .DAY ONE...THIS AFTERNOON AND TONIGHT. HEAVY RAINFALL...PERIODS OF HEAVY RAINFALL WITH LOCALIZED FLOODING COULD OCCUR TODAY. .DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY. HEAVY RAINFALL...PERIODS OF HEAVY RAINFALL WITH LOCALIZED FLOODING COULD OCCUR THURSDAY. .SPOTTER INFORMATION STATEMENT... SPOTTER ASSISTANCE IS NOT ANTICIPATED AT THIS TIME. AMZ330-350-352-354-374-301915- CHARLESTON HARBOR- WATERS FROM SOUTH SANTEE RIVER TO EDISTO BEACH SC OUT 20 NM- WATERS FROM EDISTO BEACH SC TO SAVANNAH GA OUT 20 NM- WATERS FROM SAVANNAH GA TO ALTAMAHA SOUND GA OUT 20 NM...INCLUDING GRAYS REEF NATIONAL MARINE SANCTUARY- WATERS FROM SAVANNAH GA TO ALTAMAHA SOUND GA EXTENDING FROM 20 TO 60 NM- 315 PM EDT WED AUG 29 2012 THIS HAZARDOUS WEATHER OUTLOOK IS FOR ATLANTIC COASTAL WATERS. .DAY ONE...THIS AFTERNOON AND TONIGHT. THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW. .DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY. THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW. .SPOTTER INFORMATION STATEMENT... SPOTTER ASSISTANCE IS NOT ANTICIPATED AT THIS TIME. GAZ117-119-139-141-SCZ048-049-051-301915- COASTAL BRYAN-COASTAL CHATHAM-COASTAL LIBERTY-COASTAL MCINTOSH- BEAUFORT-COASTAL COLLETON-COASTAL JASPER- 315 PM EDT WED AUG 29 2012 ...MODERATE RISK FOR RIP CURRENTS IN EFFECT UNTIL 8 PM EDT THIS EVENING... THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTHEAST GEORGIA AND SOUTHEAST SOUTH CAROLINA. .DAY ONE...THIS AFTERNOON AND TONIGHT. PLEASE LISTEN TO NOAA WEATHER RADIO OR GO TO WEATHER.GOV ON THE INTERNET FOR MORE INFORMATION ABOUT THE FOLLOWING HAZARDS. MODERATE RISK FOR RIP CURRENTS. HEAVY RAINFALL...PERIODS OF HEAVY RAINFALL WITH LOCALIZED FLOODING COULD OCCUR TODAY. .DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY. HEAVY RAINFALL...PERIODS OF HEAVY RAINFALL WITH LOCALIZED FLOODING COULD OCCUR THURSDAY. .SPOTTER INFORMATION STATEMENT... SPOTTER ASSISTANCE IS NOT ANTICIPATED AT THIS TIME. SCZ052-301915- TIDAL BERKELEY- 315 PM EDT WED AUG 29 2012 ...FLASH FLOOD WATCH IN EFFECT UNTIL 11 PM EDT THIS EVENING... THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTHEAST SOUTH CAROLINA. .DAY ONE...THIS AFTERNOON AND TONIGHT. PLEASE LISTEN TO NOAA WEATHER RADIO OR GO TO WEATHER.GOV ON THE INTERNET FOR MORE INFORMATION ABOUT THE FOLLOWING HAZARDS. FLASH FLOOD WATCH. .DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY. HEAVY RAINFALL...PERIODS OF HEAVY RAINFALL WITH LOCALIZED FLOODING COULD OCCUR THURSDAY. .SPOTTER INFORMATION STATEMENT... SPOTTER ASSISTANCE IS NOT ANTICIPATED AT THIS TIME.
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE CHARLESTON SC
345 PM EDT WED AUG 29 2012
SCZ045-292015-
INLAND BERKELEY-
345 PM EDT WED AUG 29 2012
...MARINERS ON LAKE MOULTRIE SHOULD SEEK SAFE HARBOR...
AT 342 PM EDT...NATIONAL WEATHER SERVICE METEOROLOGISTS DETECTED
STRONG THUNDERSTORMS...ALONG A LINE EXTENDING FROM EASTERN LAKE
MARION TO 6 MILES NORTHEAST OF BONNEAU BEACH...MOVING EAST AT 25
MPH.
MARINERS ON THE LAKE SHOULD PREPARE NOW FOR THE FOLLOWING HAZARDS...
GUSTY WINDS OF 25 TO 30 MPH...
CLOUD TO LAKE LIGHTNING...
PRECAUTIONARY/PREPAREDNESS ACTIONS...
THESE STORMS ARE EXPECTED TO IMPACT LAKE MOULTRIE. BOATERS SHOULD
SEEK SAFE HARBOR IMMEDIATELY. IF CAUGHT ON THE OPEN WATERS...STAY AS
LOW AS POSSIBLE AND WEAR A PERSONAL FLOATATION DEVICE. SWIMMERS
SHOULD GET OUT OF THE WATER AND INTO A STURDY BUILDING. REMEMBER...IF
YOU CAN HEAR THUNDER YOU ARE AT RISK OF BEING STRUCK BY LIGHTNING.
&&
LAT...LON 3340 8008 3339 7999 3328 7997 3328 8015
3334 8014
TIME...MOT...LOC 1945Z 268DEG 21KT 3340 8009 3339 7992PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE CHARLESTON SC
708 PM EDT WED AUG 29 2012
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0706 PM HEAVY RAIN 12 NE CHARLESTON 32.90N 79.78W
08/29/2012 M3.63 INCH CHARLESTON SC AWOS
MOUNT PLEASANT REGIONAL AIRPORT RECORDED 3.63 INCHES OF
RAIN SINCE 615 PM.
&&
EVENT NUMBER CHS1200741PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE CHARLESTON SC
721 PM EDT WED AUG 29 2012
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0711 PM HEAVY RAIN 4 NNW CAPERS INLET 32.90N 79.73W
08/29/2012 E0.00 INCH CHARLESTON SC TRAINED SPOTTER
4 TO 5 INCHES OF STANDING WATER ON HIGHWAT 17. THE ROAD
IS STILL PASSABLE.
&&
EVENT NUMBER CHS1200742PRELIMINARY LOCAL STORM REPORT...CORRECTED
NATIONAL WEATHER SERVICE CHARLESTON SC
723 PM EDT WED AUG 29 2012
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0711 PM HEAVY RAIN 4 NNW CAPERS INLET 32.90N 79.73W
08/29/2012 E0.00 INCH CHARLESTON SC TRAINED SPOTTER
4 TO 5 INCHES OF STANDING WATER ON HIGHWAY 17. THE ROAD
IS STILL PASSABLE.
&&
CORRECTED REMARKS
EVENT NUMBER CHS1200742
VBThe Charleston,SC radar (KCLX), 118 km away, was scanning. The volume nearest the first event began at 23:37 UTC.
8 flash flood. Local standard time, as filed.
Law enforcement reports that police are assisting a motorist stranded in high water.
Emergency management reports several roads closed due to flooding including Ashley Avenue at Bennett Street, parts of Morrison Drive, Market Street, and Church Street.
The public reports at least two feet of water on Coleman Boulevard in front of Moultrie Middle School.
Emergency management reports several other roads closed including America, Reid, President at the Crosstown, Concord, and Hazel.
The following intersections were closed due to flooding including Huger and King, and Huger and Meeting.
Through social media, a car reported flooded and blocking the road on 32nd Avenue.
A report roadway closed at Highway 125 and Highway 278 due to flooding.
Flash flooding reported on Short Street in Allendale.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in South Carolina in 2012Every state in 2012This day in weather historyWarnings in South Carolina, August 2012
NOAA National Centers for Environmental Information, Storm Events Database, compiled from the National Weather Service’s monthly Storm Data. Complete through 2026-06; NCEI adds each month about 75 days after it ends and revises past years a few times a year. Rebuilt 2026-09-24. Each event’s entry at NCEI: 410783, 410785, 410786, 410787, 410788, 410789, 410790, 410791.