A stationary frontal boundary in combination with the inland propagating sea breeze, resulted in scattered thunderstorm development across southern 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 stationary frontal boundary in combination with the inland propagating sea breeze, resulted in scattered thunderstorm development across southern 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 4, 2:52 PM EST, 1 hour 2 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON SC 352 PM EDT TUE AUG 4 2009 .SYNOPSIS... THIS WEEK...A LARGE AREA OF SURFACE HIGH PRESSURE IN THE CENTRAL AND WESTERN ATLANTIC WILL CONTINUE TO RIDGE INTO THE AREA INTO THE FIRST PART OF NEXT WEEK. A SURFACE TROUGH WILL ALSO PERSIST INLAND THIS WEEK. && .NEAR TERM /UNTIL 6 AM WEDNESDAY MORNING/... THE SEA BREEZE...AN INLAND DEWPOINT BOUNDARY AND THUNDERSTORM OUTFLOW BOUNDARIES WILL CONTINUE TO DRIVE ISOLATED/SCATTERED DIURNAL THUNDERSTORMS INTO THIS EVENING...WITH THE FOCUS OF THUNDERSTORMS GRADUALLY SHIFTING INLAND WITH THE ADVANCING SEA BREEZE. STRONG INSTABILITY AND MID LEVEL DRY AIR/DOWNDRAFT CAPES AS HIGH AS 1500 J/KG WILL SUPPORT THE THREAT FOR ISOLATED/BRIEF PULSE SEVERE THUNDERSTORMS WITH DAMAGING WIND GUSTS AND EVEN LARGE HAIL...ESPECIALLY WHERE BOUNDARY COLLISIONS ENHANCE UPDRAFTS. PWATS 1.4 TO 1.7 INCH WILL ALSO SUPPORT AN ISOLATED EXCESSIVE RAIN THREAT WHERE THUNDERSTORMS REDEVELOP ALONG BOUNDARIES AND PERSIST OVER ANY GIVEN AREA. AFTER SUNSET...THUNDERSTORMS SHOULD QUICKLY DISSIPATE...LEAVING MOSTLY CLEAR SKIES. EXTENSIVE CIRRUS CREATED BY OHIO VALLEY THUNDERSTORM COMPLEXES WILL ATTEMPT TO SPILL SE BUT SHOULD HAVE MINIMAL IMPACT ON SKY COVER. ONCE AGAIN...ISOLATED THUNDERSTORMS SHOULD DEVELOP LATE TONIGHT WHERE LOW LEVEL CONVERGENCE DEVELOPS OVER THE COASTAL WATERS...MOST LIKELY WELL EAST OF COASTAL COUNTIES. && .SHORT TERM /6 AM WEDNESDAY MORNING THROUGH WEDNESDAY NIGHT/... ASIDE FROM ISOLATED THUNDERSTORMS OVER MARINE AREAS TO START...WEDNESDAY WILL START MOSTLY SUNNY ACROSS THE REGION. THEN... EXPECT ANOTHER ROUND OF DIURNAL THUNDERSTORMS...JUSTIFYING SLIGHT CHANCE TO CHANCE POPS...MAINLY ALONG THE SEA BREEZE WHICH WILL ADVANCE INLAND DURING THE AFTERNOON/EARLY EVENING. STRONG INSTABILITY... WEAK STEERING WINDS AND PWATS 1.5 TO 2 INCHES WILL AGAIN SUPPORT A LOCAL THREAT FOR ISOLATED/BRIEF PULSE SEVERE THUNDERSTORMS AND LOCALLY EXCESSIVE RAINFALL. ALSO OF NOTE...12Z GUIDANCE SUGGESTS THAT AN UPPER TROUGH WILL DEVELOP JUST WEST OF THE REGION WEDNESDAY...ESPECIALLY DURING THE AFTERNOON/EVENING. THIS SHOULD SHARPEN THE INLAND SURFACE TROUGH...AND ENHANCED CONVERGENCE/0-6 KM BULK SHEAR INCREASING TO AROUND 20 KNOTS COULD SUPPORT MULTICELL THUNDERSTORMS WHICH IF SUFFICIENTLY INTENSE/ORGANIZED COULD PUSH INTO AT LEAST INLAND COUNTIES DURING THE LATE AFTERNOON OR EVENING. THUS...MAINTAINED SLIGHT CHANCE POPS UNTIL 06Z THURSDAY MORNING. && .LONG TERM /THURSDAY THROUGH TUESDAY/... UPPER LEVEL TROUGH OVER THE SOUTHEASTERN STATES ON THURSDAY WILL WEAKEN AS AN UPPER LEVEL HIGH PRESSURE RIDGE BUILDS OVER THE SOUTHEASTERN STATES...GULF COAST STATES AND MID MISSISSIPPI VALLEY OVER THE WEEKEND AND INTO THE FIRST PART OF NEXT WEEK. THE UPPER LEVEL TROUGH...COMBINED WITH PRECIPITABLE WATER VALUES AROUND 2 INCHES...DECENT INSTABILITY AND THE SEA BREEZE WILL LIKELY RESULT IN SCATTERED MAINLY AFTERNOON AND EVENING SHOWERS AND THUNDERSTORMS ON THURSDAY. WILL CONTINUE TO ADVERTISE RAIN CHANCES IN THE 30 TO 40 PERCENT RANGE FOR MOST. SOME OF THE THUNDERSTORMS WILL PRODUCE HEAVY RAINFALL. LOWERED THE HIGH TEMPERATURE FORECAST SLIGHTLY TO ACCOUNT FOR MORE CLOUD COVER THAN PREVIOUSLY THOUGHT AND GOOD PENETRATION OF THE SEA BREEZE. MODELS ALL AGREE THAT THE UPPER LEVEL RIDGE WILL DEVELOP STARTING ON FRIDAY AND PERSIST INTO EARLY NEXT WEEK...BUT DIFFER ON THE LOCATION. FAVOR THE FARTHER WEST SOLUTION OF THE ECMWF THIS WEEKEND WHICH WOULD RESULT IN THE POTENTIAL FOR AN MCS TO MAKE A RUN AT THE AREA ON SUNDAY AFTERNOON/EVENING. OTHERWISE...EXPECT SOME AFTERNOON AND EVENING THUNDERSTORMS EACH DAY...MAINLY ALONG SEA BREEZE...BUT LACK OF DEEP MOISTURE AND GENERAL SINKING MOTION SHOULD LIMIT COVERAGE. HIGHS OVER THE WEEKEND AND INTO EARLY NEXT WEEK WILL MAINLY BE IN THE MID 90S WELL AWAY FROM THE COAST WITH UPPER 80S AND LOWER 90S CLOSER TO THE COAST. && .AVIATION /20Z TUESDAY THROUGH SUNDAY/... OUTSIDE THUNDERSTORMS...EXPECT MAINLY VFR CONDITIONS FOR KCHS AND KSAV THROUGH THE 18Z TAF PERIOD. WITH PLENTY OF INSTABILITY ACROSS THE AREA THIS AFTERNOON...EXPECT SCATTERED THUNDERSTORMS TO CONTINUE TO DEVELOP ACROSS THE AREA...ALONG THE SEABREEZE AND OUTFLOW BOUNDARIES. THUS HAVE INCLUDED TEMPO GROUPS THUNDERSTORMS WITH GUSTY/SHIFTING WINDS AND MVFR CONDITIONS AT KCHS AND KSAV UNTIL 22Z. WILL AMEND IF THUNDERSTORMS BECOME MORE INTENSE. THE THREAT OF THUNDERSTORMS WILL DIMINISH AROUND SUNSET WITH WINDS DROPPING OFF AND MAINLY CLEAR SKIES PREVAILING OVERNIGHT. THESE CONDITIONS ALONG WITH LINGERING MOISTURE COULD LEAD TO PATCHY MVFR FOG DEVELOPMENT EARLY WEDNESDAY MORNING. YET POTENTIAL REMAINS TOO LOW AT THIS TIME TO INCLUDE IN TAFS. EXPECT ISOLATED TO SCATTERED DEVELOPMENT AGAIN WEDNESDAY AFTERNOON. EXTENDED AVIATION OUTLOOK...MAINLY VFR CONDITIONS WILL PREVAIL OUTSIDE OF ANY ISOLATED TO SCATTERED DIURNAL CONVECTION THROUGH SATURDAY. && .MARINE... EXPECT ANOTHER MODEST SURGE OF S/SW WINDS TONIGHT...COMPARABLE TO RECENT NIGHTS WITH WINDS REMAINING AT OR BELOW 20 KNOTS AND SEAS NO HIGHER THAN 2-3 FT...PERHAPS BRIEFLY AS HIGH AS 4 FT BEYOND 20 NM. WINDS SHOULD THEN DIMINISH LATE TONIGHT/EARLY WEDNESDAY. WEDNESDAY...THE SEA BREEZE CIRCULATION SHOULD BECOME WELL ESTABLISHED BY EARLY AFTERNOON WEDNESDAY. WINDS/SEAS WILL REMAIN BELOW SMALL CRAFT ADVISORY LEVELS. WEDNESDAY NIGHT...IN RESPONSE TO A STRENGTHENING INLAND TROUGH AT THE SURFACE AND ALOFT...THE POTENTIAL EXISTS FOR A SOMEWHAT STRONGER NOCTURNAL SURGE OF S/SW WINDS...WITH GUSTS PERHAPS APPROACHING SMALL CRAFT ADVISORY THRESHOLDS ESPECIALLY BEYOND 20 NM. HOWEVER...GUIDANCE STILL FAVORS WINDS AT OR BELOW 20 KNOTS AND SEAS NO HIGHER THAN 2-4 FT. FAIRLY TRANQUIL CONDITIONS EXPECTED THROUGH SUNDAY WITH MAINLY SOUTH TO SOUTHWEST WINDS AT OR BELOW 15 KNOTS. LATE AFTERNOON AND NOCTURNAL SURGES MAY BRIEFLY PUSH WINDS ABOVE 15 KNOTS...BUT WINDS EXPECTED TO REMAIN BELOW 20 KNOTS SO THERE ARE NO SMALL CRAFT ADVISORY CONCERNS THROUGH SUNDAY. WAVES GENERALLY IN THE 2 TO 4 FOOT RANGE THROUGH THE PERIOD OUTSIDE OF THUNDERSTORM ACTIVITY. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...NONE. SC...NONE. MARINE...NONE. &&
HAZARDOUS WEATHER OUTLOOK...UPDATED NATIONAL WEATHER SERVICE CHARLESTON SC 1219 PM EDT TUE AUG 4 2009 AMZ330-350-352-354-374-GAZ087-088-099>101-114>119-137>141-SCZ040- 042>045-047>051-051000- 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-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-BERKELEY-INLAND JASPER- BEAUFORT-COASTAL COLLETON-CHARLESTON-COASTAL JASPER- 1219 PM EDT TUE AUG 4 2009 ...ISOLATED SEVERE THUNDERSTORMS THIS AFTERNOON AND EVENING... THIS HAZARDOUS WEATHER OUTLOOK IS FOR ATLANTIC COASTAL WATERS...SOUTHEAST GEORGIA AND SOUTHEAST SOUTH CAROLINA. .DAY ONE...THIS AFTERNOON AND TONIGHT. SEVERE THUNDERSTORMS...AS THE SEA BREEZE PUSHES INLAND...A FEW THUNDERSTORMS WILL DEVELOP THIS AFTERNOON INTO EARLY EVENING. ISOLATED THUNDERSTORMS COULD BRIEFLY BECOME SEVERE WITH DAMAGING WIND GUSTS EXCEEDING 60 MPH AND HAIL THE SIZE OF PENNIES OR LARGER. OTHER POTENTIAL HAZARDS INCLUDE LOCALLY EXCESSIVE RAINFALL AND FREQUENT CLOUD TO GROUND LIGHTNING. BETWEEN 3 PM AND 8 PM... ANY ISOLATED SEVERE THUNDERSTORMS WOULD MOST LIKELY OCCUR IN SOUTHERN SOUTH CAROLINA ALONG AND EAST OF INTERSTATE 95 BUT INLAND FROM AREA BEACHES...AND ACROSS SOUTHEAST GEORGIA ALONG AND SOUTH OF INTERSTATE 16. A FEW STRONG THUNDERSTORMS THAT DEVELOP OVER LAND COULD PUSH INTO ADJACENT COASTAL WATERS WITH GUSTY WINDS THIS AFTERNOON AND EVENING. CHECK WITH NOAA WEATHER RADIO ALL HAZARDS OR LOCAL MEDIA OUTLETS FOR ADDITIONAL INFORMATION TODAY. IF YOU PLAN OUTDOOR ACTIVITIES... REMAIN ALERT FOR THUNDERSTORMS. .DAYS TWO THROUGH SEVEN...WEDNESDAY THROUGH MONDAY. NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION MAY BE NEEDED THIS AFTERNOON AND EVENING.
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE CHARLESTON SC 420 PM EDT TUE AUG 4 2009 SCZ043>045-049-050-042045- BERKELEY-CHARLESTON-COASTAL COLLETON-DORCHESTER-INLAND COLLETON- 420 PM EDT TUE AUG 4 2009 ...STRONG THUNDERSTORMS WILL IMPACT NORTHERN CHARLESTON...EAST CENTRAL COLLETON...SOUTHEASTERN DORCHESTER AND SOUTHERN BERKELEY COUNTIES THROUGH 445 PM EDT... AT 419 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A LINE OF STRONG THUNDERSTORMS CAPABLE OF PRODUCING GUSTY WINDS OF 35 TO 45 MPH. THESE STORMS WERE LOCATED ALONG A LINE EXTENDING FROM WANDO TO ROUND O...OR ALONG A LINE EXTENDING FROM 15 MILES EAST OF GOOSE CREEK TO 8 MILES EAST OF WALTERBORO...MOVING SOUTHEAST AT 5 MPH. AREAS IN AND AROUND OAKBROOK...OTRANTO...COTTAGEVILLE...COOKE CROSSROADS...RED BANK LANDING...NORTHWOODS MALL...WANDO...WILL BE IMPACTED THROUGH 445 PM EDT. PRECAUTIONARY/PREPAREDNESS ACTIONS... FREQUENT CLOUD-TO-GROUND LIGHTNING CAN BE EXPECTED. IF TIME PERMITS...UNPLUG COMPUTERS...TELEVISION SETS...CABLE MODEMS AND OTHER HOME APPLIANCES AS THEY ARE SUSCEPTIBLE TO POWER SURGES AND MAY BE DAMAGED BY NEARBY LIGHTNING STRIKES. 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. PLEASE CONTACT THE NATIONAL WEATHER SERVICE IN CHARLESTON TOLL FREE AT 1-888-383-2024 IF YOU OBSERVE SEVERE WEATHER SUCH AS HAIL...DOWNED TREES...LIMBS AND POWER LINES. &&
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE CHARLESTON SC 446 PM EDT TUE AUG 4 2009 SCZ043>045-049-050-042130- BERKELEY-CHARLESTON-COASTAL COLLETON-DORCHESTER-INLAND COLLETON- 446 PM EDT TUE AUG 4 2009 ...STRONG THUNDERSTORMS WILL IMPACT NORTHERN CHARLESTON...EAST CENTRAL COLLETON...SOUTHEASTERN DORCHESTER AND SOUTHERN BERKELEY COUNTIES THROUGH 530 PM EDT... AT 444 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A LINE OF STRONG THUNDERSTORMS CAPABLE OF PRODUCING GUSTY WINDS OF 35 TO 45 MPH. THESE STORMS WERE LOCATED ALONG A LINE EXTENDING FROM SMITH TO COTTAGEVILLE...OR ALONG A LINE EXTENDING FROM 16 MILES EAST OF GOOSE CREEK TO 11 MILES EAST OF WALTERBORO...MOVING SOUTHEAST AT 5 MPH. AREAS IN AND AROUND POPPENHEIM CROSSING...COOKE CROSSROADS... NORTHWOODS MALL...RED BANK LANDING...GETTYSVILLE...CLUBHOUSE CROSSROADS...MIDLAND PARK...CLUBHOUSE CROSSROADS...WILL BE IMPACTED THROUGH 530 PM EDT. PRECAUTIONARY/PREPAREDNESS ACTIONS... FREQUENT CLOUD-TO-GROUND LIGHTNING IS OCCURRING. POSTPONE OUTDOOR ACTIVITIES PROMPTLY. SEEK SHELTER INSIDE AN ENCLOSED BUILDING. THIS THUNDERSTORM IS CAPABLE OF PRODUCING VERY HEAVY RAIN...WHICH MAY FLOOD DITCHES AND LOW-LYING AREAS. REDUCE VEHICLE SPEED TO LOWER THE RISK OF HYDROPLANING. DO NOT DRIVE INTO PLACES WHERE WATER COVERS THE ROAD. SEEK AN ALTERNATE ROUTE. 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. PLEASE CONTACT THE NATIONAL WEATHER SERVICE IN CHARLESTON TOLL FREE AT 1-888-383-2024 IF YOU OBSERVE SEVERE WEATHER SUCH AS HAIL...DOWNED TREES...LIMBS AND POWER LINES. &&
The Charleston,SC radar (KCLX), 87 km away, was scanning. The volume nearest the first event began at 20:56 UTC.
3 hail, 2 thunderstorm wind. Local standard time, as filed.
A trained weather spotter reported quarter size hail at Dorchester Lanes on Dorchester Road, 4 miles south of Summerville, South Carolina.
The public reported quarter size hail in Ladson, South Carolina.
A trained weather spotter reported penny size hail in the Village Green subdivision, 4 miles northwest of West Ashley, South Carolina.
The broadcast media relayed a report of a tree blown down along Highway 61 in the MacLaura Hall subdivision, 4 miles northwest of West Ashley, South Carolina.
The broadcast media relayed a report of high winds blowing a large tree limb through the roof and onto the floor of a residence in the Carolina Bay subdivision, 4 miles west-northwest of West Ashley, South Carolina.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in South Carolina in 2009Every state in 2009This day in weather historyWarnings in South Carolina, August 2009
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 2026-09-30. Each event’s entry at NCEI: 191331, 191326, 191327, 191330, 191328.