A cluster of stationary thunderstorms produced flash flooding in the 5-points area of Columbia and also below the USC soccer stadium at Main and Whaley Streets. Damage was minimal.
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The episode as NWS CAE wrote it up.
A cluster of stationary thunderstorms produced flash flooding in the 5-points area of Columbia and also below the USC soccer stadium at Main and Whaley Streets. Damage was minimal.
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 Columbia, SC wrote its last area forecast discussion before the first event at Aug 23, 3:08 PM EST, 2 hours 7 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE COLUMBIA SC ISSUED BY NATIONAL WEATHER SERVICE CHARLESTON SC 408 PM EDT THU AUG 23 2012 .SYNOPSIS... HIGH PRESSURE WILL REMAIN ACROSS THE REGION THROUGH THE WEEKEND...BEFORE ERODING FROM THE SOUTH AS TROPICAL STORM ISAAC MOVES TOWARD THE FLORIDA PENINSULA EARLY NEXT WEEK. MUCH OF THE FORECAST FOR NEXT WEEK WILL BE HIGHLY DEPENDENT ON THE TRACK AND STRENGTH OF THE TROPICAL SYSTEM. && .NEAR TERM /UNTIL 6 AM FRIDAY MORNING/... A WEAK UPPER TROUGH WILL REMAIN ACROSS CENTRAL SC/GA THROUGH TONIGHT ALTHOUGH THE BEST VORTICITY ENERGY WILL SHIFT EAST OF THE AREA BY LATE TONIGHT. PRECIPITABLE WATER RANGES FROM 1.6 TO 1.8 INCHES THIS AFTERNOON...THUS DESPITE ONLY MODEST LOW-LEVEL INSTABILITY AND FORCING WE ARE SEEING ISOLATED TO SCATTERED SHOWERS DEVELOPING. THIS ACTIVITY IS EXPECTED TO DIMINISH THIS EVENING WITH THE LOSS OF DAYTIME HEATING. MOSTLY CLOUDY SKIES WILL PREVAIL. && .SHORT TERM /6 AM FRIDAY MORNING THROUGH SUNDAY/... A WEDGE OF SURFACE HIGH PRESSURE WILL STRETCH SOUTH/SOUTHWEST FROM THE NEW ENGLAND STATES THROUGH THE FORECAST AREA BY FRIDAY. A WEAK WAVE OF LOW PRESSURE WILL BE TRAVELING UP THE CAROLINA COASTLINE AT THE SAME TIME...COINCIDENT WITH A SUBTLE UPPER LOW SHIFTING NORTH INTO THE MID ATLANTIC STATES. SUFFICIENT CONVERGENCE AND DEEP MOISTURE ASSOCIATED WITH THE COASTAL WAVE AND EMBEDDED ENERGY IN THE UPPER LOW WILL WRAP INTO CENTRAL SOUTH CAROLINA...SUPPORTING A SLIGHT CHANCE FOR SHOWERS/THUNDERSTORMS ON FRIDAY. ANY ISOLATED CONVECTION IS EXPECTED TO DISSIPATE DURING THE EVENING HOURS WITH THE DECREASE IN HEATING AND INSTABILITY. AS THE WEAK LOW ALOFT CONTINUES TO DRIFT NORTHWARD AND FARTHER FROM THE AREA...DEEP LAYER MOISTURE WILL DECREASE FOR PORTIONS OF THE SOUTHEAST STATES. WEAK AND BROAD UPPER RIDGING WILL PREVAIL...AND LACKING ANY NOTABLE SYNOPTIC LEVEL SUPPORT...EXPECT PRECIPITATION POTENTIAL TO BE REDUCED FOR SATURDAY AND SUNDAY. BOTH THE 12Z GFS AND 12Z NAM SOLUTIONS ARE RATHER DRY FOR THE WEEKEND...AND GIVEN A BUILDING WEDGE OF HIGH PRESSURE AND THE RESULTING LIGHT NORTHEAST FLOW...PREFER TO KEEP POPS BELOW 15 PERCENT BOTH DAYS. CLOUD COVER WILL BE ON A DIMINISHING TREND FRIDAY THROUGH SUNDAY...WHILE HEIGHTS ALOFT RISE WITH THE TRANSITIONING UPPER LEVEL PATTERN. ALTHOUGH THESE FEATURES WILL USUALLY SUGGEST A WARMING TREND...NORTHEAST FLOW SHOULD MITIGATE CONDITIONS A BIT...RESULTING IN HIGH TEMPERATURES A DEGREE OR TWO BELOW CLIMATOLOGICAL NORMALS. EXPECT TEMPERATURES TO PEAK IN THE UPPER 80S EACH AFTERNOON...WITH LOWS FALLING INTO THE 63 TO 68 DEGREE RANGE EACH NIGHT. && .LONG TERM /SUNDAY NIGHT THROUGH THURSDAY/... MUCH OF THE EXTENDED FORECAST IS GOING TO BE HIGHLY DEPENDENT ON IMPACTS FROM TROPICAL STORM ISAAC...AS THE SYSTEM IS EXPECTED TO MOVE ACROSS THE FLORIDA PENINSULA EARLY NEXT WEEK. SINCE THERE IS SIGNIFICANT UNCERTAINTY IN THE EVENTUAL TRACK AND INTENSITY OF ISAAC...HAVE OPTED TO MAKE VERY LITTLE CHANGE TO THE ONGOING FORECAST MONDAY AND BEYOND. A WEAKNESS IN THE BROAD UPPER RIDGE ACROSS THE SOUTHEAST STATES COULD PROVIDE AN OPPORTUNITY FOR ISAAC TO MOVE NORTHWARD LATE IN THE EXTENDED PERIOD. CONSIDERING A FLUX OF MOISTURE FROM THE SOUTH...HAVE TRENDED POPS TO 20 TO 30 PERCENT MONDAY AND TUESDAY...THEN UP TO 40 TO 50 PERCENT BY WEDNESDAY. TEMPERATURES WILL RANGE CLOSER TO NORMAL THROUGH THE PERIOD...WITH HIGHS IN THE UPPER 80S SUNDAY THROUGH TUESDAY AND LOWS IN THE MIDDLE TO UPPER 60S. INCREASING CLOUD COVER WEDNESDAY SHOULD HOLD HIGHS IN THE MIDDLE 80S WITH LOWS IN THE LOWER 70S. PLEASE REFER TO THE LATEST ADVISORIES ON TROPICAL STORM ISAAC FROM THE NATIONAL HURRICANE CENTER FOR THE LATEST FORECAST INTENSITY AND TRACK. && .AVIATION /20Z THURSDAY THROUGH TUESDAY/... MAINLY VFR CONDITIONS WILL PREVAIL...BUT ISOLATED SHOWERS COULD PERIODICALLY REDUCE CONDITIONS TO MVFR LEVELS THIS AFTERNOON. THEREFORE...HAVE INITIATED VCSH FOR ALL SITES WHILE INCLUDING A BRIEF MVFR TEMPO AT KOGB AS DEEPER MOISTURE RESIDES ACROSS THE EASTERN PORTION OF THE AREA. CONVECTION SHOULD DIMINISH FAIRLY QUICKLY THIS EVENING WITH DRY CONDITIONS PREVAILING OVERNIGHT. HOWEVER...SOME LIGHT PATCHY FOG COULD DEVELOP SEVERAL HOURS PRIOR TO SUNRISE AS LINGERING MOISTURE BECOMES TRAPPED UNDER THE INVERSION. STILL... CONFIDENCE REMAINS TOO LOW TO INCLUDE VISIBILITIES BELOW VFR FOR NOW. EXTENDED AVIATION OUTLOOK...A CHANCE OF SHOWERS AND THUNDERSTORMS... ALONG WITH A CHANCE OF LATE NIGHT/EARLY MORNING RESTRICTIONS TO CIGS/VSBYS...CAN BE EXPECTED THROUGH THE PERIOD. && .CAE WATCHES/WARNINGS/ADVISORIES... SC...NONE. GA...NONE. && JRL/79/JHP
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE COLUMBIA SC ISSUED BY NATIONAL WEATHER SERVICE CHARLESTON SC 333 PM EDT THU AUG 23 2012 GAZ040-063>065-077-SCZ015-016-018-020>022-025>031-035>038-041-241945- LINCOLN-MCDUFFIE-COLUMBIA-RICHMOND-BURKE-LANCASTER-CHESTERFIELD- MCCORMICK-NEWBERRY-FAIRFIELD-KERSHAW-EDGEFIELD-SALUDA-LEXINGTON- RICHLAND-LEE-AIKEN-SUMTER-BARNWELL-ORANGEBURG-CALHOUN-CLARENDON- BAMBERG- 333 PM EDT THU AUG 23 2012 THIS HAZARDOUS WEATHER OUTLOOK IS FOR EAST CENTRAL GEORGIA AND CENTRAL SOUTH CAROLINA. .DAY ONE...THIS AFTERNOON AND TONIGHT. SCATTERED SHOWERS AND ISOLATED THUNDERSTORMS WILL REMAIN POSSIBLE THROUGH THIS EVENING. TORRENTIAL RAINFALL MAY PRODUCE LOCALIZED FLOODING. .DAYS TWO THROUGH SEVEN...FRIDAY THROUGH WEDNESDAY. THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS NOT EXPECTED AT THIS TIME.
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE COLUMBIA SC ISSUED BY NATIONAL WEATHER SERVICE CHARLESTON SC 254 PM EDT THU AUG 23 2012 GAZ065-077-SCZ029>031-035>038-041-232100- RICHMOND-BURKE-LEE-AIKEN-SUMTER-BARNWELL-ORANGEBURG-CALHOUN- CLARENDON-BAMBERG- INCLUDING THE CITIES OF...AUGUSTA...HEPHZIBAH...WAYNESBORO... BISHOPVILLE...SAVANNAH RIVER SITE...AIKEN...NORTH AUGUSTA... SUMTER...BARNWELL...WILLISTON...BLACKVILLE...ORANGEBURG... ST. MATTHEWS...MANNING...SUMMERTON...BAMBERG...DENMARK 254 PM EDT THU AUG 23 2012 ...LOCALLY HEAVY RAINFALL POSSIBLE THIS AFTERNOON... SCATTERED SHOWERS AND THUNDERSTORMS WILL CONTINUE TO DEVELOP ACROSS PARTS OF THE SOUTHERN MIDLANDS OF SOUTH CAROLINA AS WELL AS THE CENTRAL SAVANNAH RIVER AREA OF EASTERN GEORGIA THROUGH THE REMAINDER OF THE AFTERNOON HOURS. ANY THUNDERSTORMS THAT DEVELOP WILL BE SLOW MOVING AND CAPABLE OF PRODUCING TORRENTIAL DOWNPOURS. LOCALIZED RAINFALL AMOUNTS IN EXCESS OF 2 INCHES COULD OCCUR UNDER WHICH MAY RESULT IN MINOR FLOODING OF LOW LYING AND POOR DRAINAGE AREAS. STAY TUNED TO NOAA WEATHER RADIO ALL HAZARDS...TV OR YOUR LOCAL NEWS SOURCE FOR THE LATEST WEATHER INFORMATION AND POSSIBLE FLOOD ADVISORIES FROM THE NATIONAL WEATHER SERVICE.
The Columbia radar (KCAE), 10 km away, was scanning. The volume nearest the first event began at 22:14 UTC.
2 flash flood. Local standard time, as filed.
The USGS gage near the intersection of Pickens and Blossom Street reached 7.66 feet. Flood state is 7.2 feet. This produced flash flooding in the 5-points area of Columbia.
Flooding occurred at the intersection of Main and Whaley Street and along Main Street in Columbia. The USGS gage reached 7.55 feet. Flood state is 7.2 feet.
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: 393839, 393840.