A broad upper trough was in place across the eastern United States with an inland surface trough in the lee of the Appalachian Mountains. Scattered to numerous thunderstorms developed near the surface trough and affected much of Georgia and South Carolina.
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 broad upper trough was in place across the eastern United States with an inland surface trough in the lee of the Appalachian Mountains. Scattered to numerous thunderstorms developed near the surface trough and affected much of Georgia and South Carolina.
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 17, 9:53 AM EST, 2 hours 14 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON SC 1053 AM EDT FRI AUG 17 2012 .SYNOPSIS... AN INLAND TROUGH OF LOW PRESSURE WILL PREVAIL THROUGH FRIDAY. A WEAK COLD FRONT WILL APPROACH FROM THE NORTHWEST SATURDAY BEFORE STALLING JUST NORTH AND WEST OF THE AREA ON SUNDAY AS A WEAK WAVE OF LOW PRESSURE FORMS ALONG THE FRONT. THE FRONT IS EXPECTED TO SHIFT ACROSS THE AREA EARLY NEXT WEEK...THEN LINGER JUST OFFSHORE INTO THE MIDDLE OF NEXT WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... THE WEAK SHORT WAVE DISTURBANCE THAT IS MOVING ACROSS SOUTHWEST GEORGIA THIS MORNING HAS HELPED TO TRIGGER ISOLATED SHOWERS ALONG THE COAST FROM BEAUFORT SOUTHWARD TO MCINTOSH COUNTY. HAVE INCREASED POPS TO ACCOUNT FOR THIS ACTIVITY...WHICH WILL LIKELY BE SHORT LIVED THIS MORNING. THE LATEST SOUNDING FROM KCHS SHOWED CAPES NEAR 3000 J/KG AND MUCH HIGHER DOWNDRAFT CAPES THAN YESTERDAY AT OVER 1300 J/KG. THE SHORTWAVE MENTIONED ABOVE OVER S GA SHOULD BE MOVING EASTWARD OUT OF THE REGION THIS AFTERNOON...MAKING IT LESS OF A PLAYER FOR CONVECTION THIS AFTERNOON. THE OTHER POTENTIAL PLAYER TO PROVIDE UPPER SUPPORT AND LOW LEVEL BOUNDARY COLLISIONS WOULD BE FROM THE DISSIPATING MCS DROPPING SOUTH-SOUTHEAST ACROSS MISSISSIPPI AND ALABAMA. HOWEVER...THIS FEATURE IS PRETTY FAR AWAY AND IF IT DID HAVE AN IMPACT ON CONVECTION IT WOULD BE LATER TODAY AND INTO THIS EVENING. FINALLY...AT THE SURFACE...A WEAK TROUGH OF LOW PRESSURE APPEARS WILL REMAIN OVER THE INTERIOR...ACTING AS A POTENTIAL LOW LEVEL FOCUS FOR AFTERNOON ACTIVITY ALONG WITH A LATE AFTERNOON RESULTANT/SOUTHWESTERLY SEA BREEZE CLOSER TO THE COAST. IN SUMMARY...GIVEN THE INLAND TROUGH OF LOW PRESSURE...MODERATE INSTABILITY AND DOWNDRAFT CAPES...AND THE POTENTIAL FOR CONVECTIVE BOUNDARIES TO MOVE IN FROM THE WEST FROM THE OLD MCS...HAVE INCREASED POPS A TAD FOR THIS AFTERNOON ACROSS THE ENTIRE AREA. THE HIGHEST CHANCES ARE STILL OVER THE SOUTHERN 1/2 OF THE REGION AND CLOSER TO THE COAST WHERE THE DEEPEST MOISTURE AND INSTABILITY WILL RESIDE. HOWEVER... GIVEN THE POTENTIAL FOR BOUNDARY COLLISIONS ON THE MESOSCALE...TRYING TO NAIL DOWN THE EXACT LOCATION FOR THE HIGHEST POPS IS VERY DIFFICULT AT THIS TIME. THICKER CLOUD COVER CURRENTLY OVER THE SOUTHERN HALF OF THE AREA WILL SLOW DOWN TEMP RISES A BIT THIS MORNING...BUT THEY SHOULD BURN OFF ENOUGH TO ALLOW TEMPS TO REACH AROUND 90S TO THE LOWER 90S...AND LOWER 90S ELSE WHERE. && .SHORT TERM /6 PM THIS EVENING THROUGH MONDAY/... A FAIRLY STRONG SHORT WAVE WILL APPROACH FROM THE WEST THIS EVENING THEN SHIFT ACROSS THE AREA OVERNIGHT. THIS WILL ENHANCE THE LEE SIDE TROUGH AT THE SURFACE AND ALLOW IT TO SHIFT CLOSER TOWARD THE COAST AS THE NIGHT PROGRESSES. GIVEN THIS SCENARIO...THE FORECAST WILL SHOW A CHANCE OF SHOWERS AND THUNDERSTORMS IN MOST AREAS THIS EVENING...LOWERING TO A SLIGHT CHANCE OVERNIGHT. THE POSSIBILITY FOR ISOLATED SEVERE THUNDERSTORMS WILL CONTINUE INTO THE EVENING HOURS. LOWS SHOULD BE IN THE LOWER 70S ACROSS MUCH OF THE AREA. SATURDAY AND SATURDAY NIGHT...HEIGHTS WILL BEGIN TO LOWER IN RESPONSE TO A DEVELOPING UPPER TROUGH ACROSS THE EASTERN HALF OF THE UNITED STATES. AT THE SURFACE...A COLD FRONT WILL REMAIN NORTHWEST OF THE FORECAST AREA STALLED ACROSS THE UPSTATE. MODELS SHOW INCREASING MOISTURE WITH PWATS CLIMBING CLOSE TO 2 INCHES...AND WITH SOME WEAK SHORT WAVE SWINGING ACROSS THE AREA...EXPECT SCATTERED SHOWERS AND A FEW THUNDERSTORMS TO DEVELOP. INSTABILITY PARAMETERS INDICATE MODERATE INSTABILITY ACROSS THE AREA...BUT LAPSE RATES APPEAR LESS THAN IMPRESSIVE. THUS...CAN NOT RULE OUT A FEW STRONG TO SEVERE STORMS...BUT OVERALL EXPECT SEVERE POTENTIAL TO REMAIN NORTHWEST OF THE FORECAST AREA CLOSER TO THE STALLED FRONT. CONVECTION IS EXPECTED TO DIMINISH AFTER SUNSET DUE TO THE LOSS OF DAYTIME HEATING...HOWEVER SOME LINGERING CONVECTION COULD PERSIST UNTIL CLOSE TO MIDNIGHT DUE TO BOUNDARY INTERACTIONS. INCREASING CLOUD COVERAGE THROUGH THE DAY COULD LIMIT HIGH TEMPERATURES A BIT...BUT STILL EXPECT TEMPERATURES TO REACH THE LOW 90S AWAY FROM THE COAST ON SATURDAY WITH TEMPERATURES FALLING INTO THE MID TO LOW 70S DURING THE OVERNIGHT HOURS. SUNDAY THROUGH MONDAY...THE UPPER TROUGH WILL CONTINUE TO DEEPEN ACROSS THE EAST COAST AS ITS ASSOCIATED COLD FRONT REMAINS STALLED JUST INLAND OF THE FORECAST AREA ON SUNDAY. THE FRONT WILL THEN PUSH TOWARD THE COASTLINE ON MONDAY WHILE PLENTY OF DEEP MOISTURE FILTERS ACROSS THE REGION. AMPLE MOISTURE IS WELL NOTED ON MODEL SOUNDINGS FOR BOTH AFTERNOONS WITH PWATS OVER 2 INCHES. ALSO...THE SYNOPTIC LIFT LOOKS MORE IMPRESSIVE AS THE AS THE UPPER JET STRETCHES FROM THE LOWER MISSISSIPPI VALLEY UP TO THE NEW ENGLAND AREA. HOWEVER...INSTABILITY FACTORS COULD BE LIMITED SOME AS CLOUD COVERAGE COULD KEEP AFTERNOON HIGH TEMPERATURES SEVERAL DEGREES BELOW SEASONAL NORMAL. THUS AT THIS POINT...THE MAIN HAZARD LOOKS TO BE PERIODS OF HEAVY RAINFALL. && .LONG TERM /MONDAY NIGHT THROUGH THURSDAY/... THE UPPER TROUGH WILL REMAIN ANCHORED ACROSS THE EASTERN HALF OF THE UNITED STATES THROUGH MID WEEK. INITIALLY A STALLED COLD FRONT WILL REMAIN OFFSHORE BEFORE PULLING AWAY FROM THE AREA AROUND WEDNESDAY. THE UPPER TROUGH WILL BEGIN TO WEAKEN THEREAFTER...BUT MODELS STILL SHOW A SERIES OF WEAK DISTURBANCES SWINGING ACROSS THE AREA. OVERALL...EXPECT ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS THROUGH THE EXPENDED PERIOD...ESPECIALLY DURING THE TRADITIONAL AFTERNOON HOURS. SLIGHTLY BELOW NORMAL TEMPERATURES ARE ALSO EXPECTED TO CONTINUE WITH HIGHS IN THE UPPER 80S AND LOWS POSSIBLY DIPPING INTO THE MID TO UPPER 60S. && .AVIATION /15Z FRIDAY THROUGH TUESDAY/... VFR CONDITIONS ARE EXPECTED TO PREVAIL AT KCHS AND KSAV THROUGH 12Z SATURDAY. ISOLATED TO SCATTERED SHOWERS AND THUNDERSTORMS ARE POSSIBLE THIS AFTERNOON INTO THIS EVENING...WITH THE GREATEST COVERAGE ACROSS SOUTHEAST GEORGIA. CONVECTION MAY EVENTUALLY NEED TO BE INCLUDED IN THE TAF/S...ESPECIALLY AT KSAV...BUT CONFIDENCE IN TIMING IS STILL TOO UNCERTAIN. EXTENDED AVIATION OUTLOOK...THERE IS A CHANCE OF SOME LOW CLOUDS AROUND EACH MORNING THROUGH THE WEEKEND...POSSIBLY ENOUGH TO LOWER CIGS TO MVFR FOR AN HOUR OR TWO. OTHERWISE...SCATTERED SHOWERS AND THUNDERSTORMS...MAINLY DURING THE AFTERNOON/EVENING HOURS...COULD RESULT IN TEMPORARY REDUCTIONS IN CIGS/VSBYS THIS WEEKEND. && .MARINE... HAVE INCREASED RAIN CHANCES TODAY...GIVEN THE LATEST CONVECTION OVER THE NEAR SHORE WATERS. HAVE ALSO LOWER WIND SPEEDS A LITTLE FOR THIS AFTERNOON...GIVEN TREND OVER THE PAST FEW DAYS HAS BEEN LIGHTER WINDS THAN MODEL GUIDANCE HAS INDICATED. THUS...SOUTHWEST WINDS OF 15 KTS OR LESS AND SEAS 3 FEET OR LESS THROUGH THE DAY. THE STRONGEST WINDS MAY BE RIGHT NEAR THE COAST WITH THE SEA BREEZE LATER IN THE AFTERNOON. A COLD FRONT WILL APPROACH FROM THE NORTHWEST THROUGH THE WEEKEND...BEFORE STALLING JUST OFF THE SOUTHEAST COAST EARLY NEXT WEEK. OVERALL...A SOUTH-SOUTHWEST FLOW IS GENERALLY EXPECTED EACH DAY...WITH THE FLOW VEERING OFFSHORE DURING THE NIGHTTIME/EARLY MORNING HOURS. GENERALLY BRIEF SURGES UPWARDS OF 15-20 KT WILL OCCUR AT TIMES...ESPECIALLY SUNDAY THROUGH MONDAY NIGHT AS THE PRESSURE GRADIENT TIGHTENS IN ASSOCIATION WITH THE APPROACHING COLD FRONT. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...NONE. SC...NONE. MARINE...NONE. && SYNOPSIS... NEAR TERM...RFM/JAQ SHORT TERM...JHP/JAQ LONG TERM...JHP AVIATION...JHP/RFM/JAQ MARINE...JHP/JAQ
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE CHARLESTON SC 457 AM EDT FRI AUG 17 2012 GAZ087-088-099>101-114>119-137>141-SCZ040-042>045-047>052-181000- JENKINS-SCREVEN-CANDLER-BULLOCH-EFFINGHAM-TATTNALL-EVANS- INLAND BRYAN-COASTAL BRYAN-INLAND CHATHAM-COASTAL CHATHAM-LONG- INLAND LIBERTY-COASTAL LIBERTY-INLAND MCINTOSH-COASTAL MCINTOSH- ALLENDALE-HAMPTON-INLAND COLLETON-DORCHESTER-INLAND BERKELEY- INLAND JASPER-BEAUFORT-COASTAL COLLETON-CHARLESTON-COASTAL JASPER- TIDAL BERKELEY- 457 AM EDT FRI AUG 17 2012 THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTHEAST GEORGIA AND SOUTHEAST SOUTH CAROLINA. .DAY ONE...TODAY AND TONIGHT. SEVERE THUNDERSTORMS...SCATTERED SHOWERS AND THUNDERSTORMS ARE EXPECTED ACROSS MUCH OF THE AREA THIS AFTERNOON INTO THIS EVENING. A FEW OF THESE THUNDERSTORMS COULD BECOME SEVERE...CAPABLE OF PRODUCING DAMAGING WINDS...LOCALLY HEAVY RAINFALL AND FREQUENT LIGHTNING. .DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY. THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW. .SPOTTER INFORMATION STATEMENT... PLEASE RELAY ANY REPORTS OF HAZARDOUS WEATHER INCLUDING...BUT NOT LIMITED TO LARGE HAIL...DAMAGING WINDS...AND FLOODING TO THE NATIONAL WEATHER SERVICE IN CHARLESTON AT 1-888-383-2024. AMZ330-350-352-354-374-181000- 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- 457 AM EDT FRI AUG 17 2012 THIS HAZARDOUS WEATHER OUTLOOK IS FOR ATLANTIC COASTAL WATERS. .DAY ONE...TODAY AND TONIGHT. THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW. .DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY. THE PROBABILITY FOR WIDESPREAD HAZARDOUS WEATHER IS LOW. .SPOTTER INFORMATION STATEMENT... SPOTTER ASSISTANCE IS NOT ANTICIPATED AT THIS TIME.
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE CHARLESTON SC
1223 PM EDT FRI AUG 17 2012
GAZ137-140-141-171700-
COASTAL MCINTOSH-INLAND MCINTOSH-LONG-
1223 PM EDT FRI AUG 17 2012
...STRONG THUNDERSTORMS WILL IMPACT PORTIONS OF LONG AND MCINTOSH
COUNTIES THROUGH 100 PM EDT...
AT 1221 PM EDT...NATIONAL WEATHER SERVICE METEOROLOGISTS DETECTED
STRONG THUNDERSTORMS...ALONG A LINE EXTENDING FROM 7 MILES WEST OF
DONALD TO 7 MILES SOUTH OF DARIEN...MOVING NORTHEAST AT 20 MPH.
SOME LOCATIONS THAT WILL BE AFFECTED INCLUDE...
CARNIGAN...COX...CRESCENT...DARIEN...DONALD...EULONIA...JONES...
LUDOWICI...MERIDIAN...PINE HARBOR...RIDGEVILLE...SAPELO ISLAND...
TIBET...TOWNSEND...VALONA AND WOLF ISLAND...
PREPARE NOW FOR THE FOLLOWING HAZARDS...
GUSTY WINDS OF 40 TO 50 MPH...
PEA TO DIME SIZE HAIL...
FREQUENT CLOUD TO GROUND LIGHTNING...
PRECAUTIONARY/PREPAREDNESS ACTIONS...
FREQUENT CLOUD-TO-GROUND LIGHTNING IS OCCURRING. POSTPONE OUTDOOR
ACTIVITIES PROMPTLY. SEEK SHELTER INSIDE AN ENCLOSED BUILDING.
BE ALERT FOR RAPIDLY CHANGING WEATHER CONDITIONS AS STORMS APPROACH.
BE READY TO TAKE IMMEDIATE ACTION IN CASE A SEVERE THUNDERSTORM
WARNING IS ISSUED FOR YOUR LOCATION.
&&
LAT...LON 3132 8136 3130 8142 3136 8154 3143 8161
3147 8162 3158 8170 3166 8185 3179 8198
3189 8189 3195 8188 3199 8181 3194 8174
3187 8176 3176 8164 3170 8148 3145 8121
3140 8125 3137 8124 3137 8127 3130 8126
TIME...MOT...LOC 1623Z 221DEG 16KT 3181 8196 3128 8142SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE CHARLESTON SC 1257 PM EDT FRI AUG 17 2012 GAZ137>140-171745- COASTAL LIBERTY-INLAND LIBERTY-INLAND MCINTOSH-LONG- 1257 PM EDT FRI AUG 17 2012 ...STRONG THUNDERSTORMS WILL IMPACT PORTIONS OF LIBERTY...LONG AND MCINTOSH COUNTIES THROUGH 145 PM EDT... AT 1256 PM EDT...NATIONAL WEATHER SERVICE METEOROLOGISTS DETECTED STRONG THUNDERSTORMS...ALONG A LINE EXTENDING FROM JONES CREEK TO JONES...MOVING NORTHEAST AT 10 MPH. SOME LOCATIONS THAT WILL BE AFFECTED INCLUDE... ALLENHURST...DONALD...FLEMINGTON...FORT STEWART...GUM BRANCH... HALFMOON LANDING...HINESVILLE...JONES...LUDOWICI...MCINTOSH... RETREAT...RICEBORO...SOUTH NEWPORT...TIBET...WALTHOURVILLE AND CROSSROADS... PREPARE NOW FOR THE FOLLOWING HAZARDS... GUSTY WINDS OF 40 TO 50 MPH... PENNY SIZE HAIL... FREQUENT CLOUD TO GROUND LIGHTNING... PRECAUTIONARY/PREPAREDNESS ACTIONS... FREQUENT LIGHTNING IS OCCURRING WITH THIS THUNDERSTORM. IF OUTDOORS...STAY AWAY FROM ISOLATED TALL OBJECTS. IF INDOORS...STAY AWAY FROM WINDOWS AND DOORS. AVOID USING PLUMBING AND ELECTRICAL APPLIANCES UNLESS IT IS AN EMERGENCY. BE ALERT FOR RAPIDLY CHANGING WEATHER CONDITIONS AS STORMS APPROACH. BE READY TO TAKE IMMEDIATE ACTION IN CASE A SEVERE THUNDERSTORM WARNING IS ISSUED FOR YOUR LOCATION. && LAT...LON 3196 8168 3169 8125 3157 8155 3181 8196 TIME...MOT...LOC 1657Z 238DEG 9KT 3181 8178 3161 8145
The Charleston,SC radar (KCLX), 111 km away, was scanning. The volume nearest the first event began at 17:07 UTC.
7 thunderstorm wind. Local standard time, as filed.
Law enforcement reported a power line down along Dunlevie Road.
The public reported one tree down along Poncell Drive.
A large tree fell on a house near Montgomery.
One tree blocking Railroad Avenue at Shipyard Road.
A large tree branch, twenty feet in length, down.
Multiple tree limbs blown down.
Multiple trees and power lines down on Waynesboro Road in the Ogeechee Farms area.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Georgia in 2012Every state in 2012This day in weather historyWarnings in Georgia, 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: 406058, 406059, 406060, 406061, 406062, 406063, 406064.