The sea breeze pushing into a highly unstable air mass, 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.
The sea breeze pushing into a highly unstable air mass, 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 Jul 31, 2:54 PM EST, 1 hour 1 minute earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON SC 354 PM EDT FRI JUL 31 2009 .SYNOPSIS... EXPECT LITTLE CHANGE IN THE PATTERN THROUGH NEXT WEEK...AS THE REGION REMAINS BETWEEN HIGH PRESSURE OVER THE WESTERN ATLANTIC AND A WEAK TROUGH OF LOW PRESSURE INLAND. && .NEAR TERM /THROUGH TONIGHT/... MOST ACTIVE PERIOD FOR CONVECTION WILL CONTINUE INTO EARLY EVENING...AS A REMNANTS OF A PROGRESSIVE MCS INTERACTS WITH THE SEA BREEZE AND ONGOING THUNDERSTORMS/ASSOCIATED OUTFLOW BOUNDARIES FROM WEST TO EAST ACROSS THE REGION. MANY LOCATIONS WILL RECEIVE MEASURABLE RAINFALL AND GUSTY THUNDERSTORMS...JUSTIFYING LIKELY/CATEGORICAL POPS MANY AREAS THROUGH EARLY EVENING. SBCAPES 3000-4000 J/KG SHOULD MAINTAIN THUNDERSTORMS TO THE COAST. A POCKET OF DRIER 700 MB AIR AND DOWNDRAFT CAPES AROUND 1000 J/KG...AS INDICATED BY THE SPC MESOANALYSIS...WILL SUPPORT A THREAT FOR BOWING SEGMENTS/OCCASIONAL DAMAGING WIND GUSTS. PWATS AROUND 2 INCHES WILL ALSO SUPPORT A LOCAL HEAVY RAIN THREAT...ESPECIALLY WHERE CELL MERGERS/BOUNDARY INTERACTIONS OCCUR. OVERNIGHT...12Z GUIDANCE SUGGESTS THAT A DIURNAL TREND TOWARD DIMINISHING SHOWER/THUNDERSTORM COVERAGE WILL DOMINATE. HOWEVER... NUMEROUS SHOWERS/THUNDERSTORMS WERE NOTED UPSTREAM. A SIMILAR REGIME FEATURING DEEP LAYER MOISTURE...LINGERING INSTABILITY AND LEFTOVER BOUNDARIES COULD SUPPORT A FEW SHOWERS/THUNDERSTORMS WELL INTO THE NIGHT. THUS...MAINTAINED SLIGHT CHANCE/CHANCE POPS OVERNIGHT. && .SHORT TERM /SATURDAY THROUGH SATURDAY NIGHT/... 12Z GUIDANCE SUGGESTS THAT A FEW SHOWERS/THUNDERSTORMS MAY BE ONGOING ALONG THE COAST/ACROSS COASTAL WATERS TO START THE DAY SATURDAY. ALSO...SOME LOCATIONS MAY START WITH STRATUS/FOG. THEN...12Z GUIDANCE SUGGESTS THAT DEEP LAYER MOISTURE...WITH 850-500 MB MEAN RH EXCEEDING 70 PERCENT...WILL SUPPORT ANOTHER ACTIVE CONVECTIVE REGIME...ESPECIALLY DURING THE AFTERNOON/EARLY EVENING. SHOWERS/THUNDERSTORMS SHOULD INITIALLY FIRE ALONG THE SEA BREEZE AND ANY DIFFERENTIAL HEATING BOUNDARIES THAT PERSIST INTO THE AFTERNOON...THEN OUTFLOW BOUNDARIES AND ANY WEAK SHORTWAVES WILL SUPPORT ADDITIONAL CONVECTION WITH MANY LOCATIONS AGAIN RECEIVING MEASURABLE RAINFALL. UNCLEAR WHETHER ADDITIONAL ORGANIZED CONVECTION WILL DEVELOP NEAR THE INLAND SURFACE TROUGH AND PUSH INTO THE REGION...AS 12Z GUIDANCE SUGGESTS THAT THE STRONGER SHEAR/JET FORCING WHICH AIDED UPSTREAM MCS DEVELOPMENT THIS AFTERNOON WILL HAVE LIFTED NORTH OF THE REGION. EVEN SO...LIKELY POPS ARE JUSTIFIED MOST AREAS DURING THE AFTERNOON. ONCE AGAIN...INSTABILITY/MOISTURE WILL SUPPORT A THREAT FOR LOCALLY EXCESSIVE RAINFALL AND ISOLATED DAMAGING WIND GUSTS. SATURDAY NIGHT...EXPECT ANOTHER ROUND OF DIURNAL WEAKENING OF SHOWERS/THUNDERSTORMS. HOWEVER...MOISTURE/INSTABILITY MAY AGAIN REMAIN SUFFICIENT TO SUPPORT A FEW SHOWERS/THUNDERSTORMS WELL INTO THE NIGHT. THUS...MAINTAINED ONGOING SLIGHT CHANCE/CHANCE POPS. && .LONG TERM /SUNDAY THROUGH FRIDAY/... ATLANTIC HIGH PRESSURE WILL REMAIN SOUTHEAST OF THE FORECAST AREA THROUGH THE EXTENDED FORECAST PERIOD...WHILE SURFACE TROUGHING PERSISTS INLAND. A BROAD UPPER TROUGH CENTERED OVER THE GREAT LAKES WILL MAINTAIN SOUTHWEST FLOW ALOFT THAT WILL CONTINUE TO SEND A SERIES OF SHORTWAVES INTO THE AREA THROUGH EARLY NEXT WEEK. STRONGEST SHORTWAVE ACTIVITY WILL MOVE SOUTHWEST ALONG THE BASE OF THE UPPER TROUGH SUNDAY AND MONDAY...WITHIN A RIBBON OF PERSISTENT DEEP LAYER MOISTURE. HAVE INDICATED HIGHEST THUNDERSTORM CHANCES ON SUNDAY IN THE LIKELY CATEGORY...WHEN THE REGION WILL BE SITUATED IN THE RIGHT REAR OF A DECENT UPPER LEVEL JET. THE COMBINATION OF IMPROVED DYNAMICS...TYPICAL SUMMERTIME SEABREEZE CONVERGENCE...AND DAYTIME INSTABILITY SUGGESTS THAT ORGANIZED STRONG TO SEVERE THUNDERSTORM DEVELOPMENT IS POSSIBLE. STORM PREDICTION CENTER MAINTAINS A 5 PERCENT SEVERE RISK OVER THE AREA FOR SUNDAY. A COLD FRONT WILL APPROACH FROM THE WEST MONDAY AND TUESDAY...STALLING JUST EAST OF THE APPALACHIANS. WEAKER SHORTWAVE ENERGY WILL CONTINUE TO STREAM INTO THE AREA EARLY NEXT WEEK. HAVE MAINTAINED SOLID CHANCE POPS MONDAY AND TUESDAY...AS FORCING FROM THE INLAND TROUGH AND AFTERNOON SEABREEZE SHOULD STILL PRODUCE SCATTERED AFTERNOON/EVENING THUNDERSTORMS WITHIN CONTINUED DEEP MOISTURE AND DECENT INSTABILITY. THE INLAND TROUGH AND UPPER SHORTWAVE ENERGY DIMINISH BY MID WEEK...AT THE SAME TIME THAT ATLANTIC RIDGING TO THE SOUTHEAST REBUILDS AND PWAT VALUES DECLINE. HAVE THUS TRENDED POP VALUES DOWNWARD INTO THE 20 TO 30 PERCENT RANGE WEDNESDAY THROUGH FRIDAY. TEMPERATURES THROUGH THE EXTENDED PERIOD WILL CONTINUE TO BE NEAR SEASONAL NORMALS. AFTERNOON HIGHS WILL REACH THE LOW 90S AWAY FROM THE COAST...WITH MID 80S CLOSER TO THE SHORES. OVERNIGHT LOWS WILL RANGE FROM THE MID 70S INLAND TO AROUND 80 NEAR THE COAST. && .AVIATION /20Z FRIDAY THROUGH WEDNESDAY/... MAIN CONCERN WILL BE THUNDERSTORMS OVER BOTH TERMINALS THIS AFTERNOON AND EVENING. LINE OF SHOWERS AND THUNDERSTORMS WILL SHIFT THROUGH THE REGION SOMETIME BETWEEN MID AFTERNOON AND EVENING. TEMPO IFR CONDITIONS AND SHIFTING WINDS WITH AT LEAST 20-25 KNOT GUSTS ARE EXPECTED BETWEEN 21Z AND 01Z AT KSAV AND KCHS. EXPECT AMENDMENTS AS NEAR TERM CONVECTIVE TRENDS BECOME CLEAR. OTHERWISE...VFR CONDITIONS ARE EXPECTED OUTSIDE THUNDERSTORM ACTIVITY. THERE IS A LOW CHANCE FOR IFR STRATUS TO DEVELOP AROUND DAYBREAK SATURDAY...ESPECIALLY AT KSAV. OUTSIDE ANY THUNDERSTORMS...STRONGEST WINDS...GUSTING TO 15-20 KNOTS...WILL OCCUR THIS AFTERNOON AND AGAIN SATURDAY AFTERNOON AS THE SEA BREEZE PUSHES THROUGH BOTH TERMINALS. EXTENDED AVIATION OUTLOOK...VFR CONDITIONS ARE EXPECTED TO PREVAIL OUTSIDE OF MAINLY AFTERNOON/EARLY EVENING SHRA/TSRA THROUGH TUESDAY. && .MARINE... THE SEA BREEZE WILL GIVE WAY TO SYNOPTIC WINDS 15-20 KNOTS...SUPPORTING SEAS 2-4 FT AND AS HIGH AS 5 FT BEYOND 20 NM...FOR A TIME BEFORE WINDS VEER TOWARD THE SW AND DIMINISH OVERNIGHT. IF ORGANIZED THUNDERSTORMS PUSH THROUGH THE WATERS THIS EVENING... THE PRESSURE PATTERN COULD BE ALTERED AND WINDS COULD ACTUALLY BECOME LIGHTER THAN EXPECTED OVERNIGHT. AFTER SW WINDS SATURDAY MORNING/EARLY AFTERNOON...EXPECT THE SEA BREEZE CIRCULATION TO AGAIN DOMINATE WIND FIELDS SATURDAY AFTERNOON/EARLY EVENING. THEN...ANOTHER NOCTURNAL SURGE OF S/SW WINDS WILL DEVELOP SATURDAY NIGHT...PUSHING WINDS TO 15-20 KNOTS AND SEAS TO 2-4 FT UNTIL LATE NIGHT. THE COASTAL WATERS WILL REMAIN UNDER THE INFLUENCE OF THE SUBTROPICAL ATLANTIC RIDGE EXTENDING WEST ACROSS FLORIDA THROUGH THE FORECAST PERIOD. A SURFACE TROUGH WILL PERSIST INLAND OVER THE SOUTHEAST STATES INTO EARLY NEXT WEEK...WITH AN OCCASIONAL PINCHING OF THE PRESSURE GRADIENT TO OCCUR BETWEEN THE TWO SYNOPTIC FEATURES. THIS PATTERN WILL RESULT IN A PERSISTENT SOUTH TO SOUTHWEST FLOW THROUGH WEDNESDAY. DESPITE ENHANCED WIND SPEEDS ALONG THE LAND/SEA INTERFACE IN CHARLESTON HARBOR...AND NOCTURNAL SURGES UNDER A MODEST LOW LEVEL JET...WIND SPEEDS WILL REMAIN BELOW ANY SMALL CRAFT ADVISORY CRITERIA. WINDS WILL BE CAPPED AT 15 TO 20 KT WITH SEAS NO MORE THAN 3 TO 4 FT. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...NONE. SC...NONE. MARINE...NONE. &&
HAZARDOUS WEATHER OUTLOOK...UPDATED NATIONAL WEATHER SERVICE CHARLESTON SC 1028 AM EDT FRI JUL 31 2009 AMZ330-350-352-354-374-GAZ087-088-099>101-114>119-137>141-SCZ040- 042>045-047>051-011000- 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- 1028 AM EDT FRI JUL 31 2009 ...ISOLATED SEVERE THUNDERSTORMS ANSD LOCALLY HEAVY RAINFALL THIS AFTERNOON AND EVENING... THIS HAZARDOUS WEATHER OUTLOOK IS FOR ATLANTIC COASTAL WATERS...SOUTHEAST GEORGIA AND SOUTHEAST SOUTH CAROLINA. .DAY ONE...TODAY AND TONIGHT. SEVERE THUNDERSTORMS...SCATTERED TO NUMEROUS SHOWERS AND THUNDERSTORMS WILL DEVELOP ACROSS SOUTHEAST SOUTH CAROLINA AND SOUTHEAST GEORGIA THIS AFTERNOON AND EVENING. A FEW OF THE THUNDERSTORMS COULD BECOME SEVERE WITH DAMAGING WIND GUSTS EXCEEDING 60 MPH. ISOLATED THUNDERSTORMS COULD ALSO PRODUCE HAIL THE SIZE OF PENNIES OR LARGER. OTHER POTENTIAL HAZARDS INCLUDE LOCALLY EXCESSIVE RAINFALL AND FREQUENT CLOUD TO GROUND LIGHTNING. STRONGEST THUNDERSTORMS...HEAVIEST RAINFALL AND ISOLATED SEVERE WEATHER WILL MOST LIKELY OCCUR BETWEEN 2 PM AND 10 PM. ANY THUNDERSTORMS THAT DEVELOP OVER LAND COULD ADVANCE INTO ADJACENT COASTAL WATERS THIS AFTERNOON AND EVENING. YOU ARE URGED TO CHECK WITH NOAA WEATHER RADIO ALL HAZARDS...TV OR YOUR LOCAL NEWS SOURCE FOR ADDITIONAL INFORMATION AND POSSIBLE WARNINGS. .DAYS TWO THROUGH SEVEN...SATURDAY THROUGH THURSDAY. 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 311 PM EDT FRI JUL 31 2009 GAZ099-114-115-312000- CANDLER-EVANS-TATTNALL- 311 PM EDT FRI JUL 31 2009 ...STRONG THUNDERSTORMS WILL IMPACT SOUTHERN CANDLER...NORTHWESTERN TATTNALL AND NORTHERN EVANS COUNTIES THROUGH 400 PM EDT... AT 308 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A STRONG THUNDERSTORM CAPABLE OF PRODUCING PEA SIZE HAIL...AND STRONG WINDS OF 40 TO 50 MPH. THIS STORM WAS LOCATED 13 MILES WEST OF REIDSVILLE...OR ABOUT OVER LYONS...MOVING EAST AT 30 MPH. AREAS IN AND AROUND REIDSVILLE...COLLINS...COBBTOWN...MANASSAS...UNDINE...BELLVILLE...AND EXCELSIOR WILL BE IMPACTED THROUGH 400 PM EDT. PRECAUTIONARY/PREPAREDNESS ACTIONS... 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. &&
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE CHARLESTON SC
345 PM EDT FRI JUL 31 2009
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0342 PM TSTM WND DMG 4 NW CLAXTON 32.20N 81.95W
07/31/2009 EVANS GA TRAINED SPOTTER
MULTIPLE TREES DOWN.
&&
JAQPRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE CHARLESTON SC
408 PM EDT FRI JUL 31 2009
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0358 PM TSTM WND DMG TISON 31.94N 82.02W
07/31/2009 TATTNALL GA LAW ENFORCEMENT
TREES DOWN.
&&
JAQSPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE CHARLESTON SC 425 PM EDT FRI JUL 31 2009 SCZ042-043-047>049-051-312100- BEAUFORT-COASTAL COLLETON-COASTAL JASPER-HAMPTON-INLAND COLLETON-INLAND JASPER- 425 PM EDT FRI JUL 31 2009 ...STRONG THUNDERSTORMS WILL IMPACT NORTHERN JASPER...NORTH CENTRAL BEAUFORT...COLLETON AND EAST CENTRAL HAMPTON COUNTIES THROUGH 500 PM EDT... AT 424 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A LINE OF STRONG THUNDERSTORMS CAPABLE OF PRODUCING STRONG WINDS OF 40 TO 50 MPH. THESE STORMS WERE LOCATED ALONG A LINE EXTENDING FROM WILLIAMS TO BLOUNTVILLE TO TILLMAN...MOVING EAST AT 25 MPH. AREAS IN AND AROUND BELLS CROSSROADS...MCPHERSONVILLE...SMYLY... YEMASSEE...SALKEHATCHIE...GILMANIA...RHODES CROSSROADS... SWITZERLAND...SPRINGTOWN...WHITE HALL...WILL BE IMPACTED THROUGH 500 PM EDT. PRECAUTIONARY/PREPAREDNESS ACTIONS... 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. &&
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE CHARLESTON SC 432 PM EDT FRI JUL 31 2009 GAZ137>141-312115- COASTAL LIBERTY-COASTAL MCINTOSH-INLAND LIBERTY-INLAND MCINTOSH-LONG- 432 PM EDT FRI JUL 31 2009 ...STRONG THUNDERSTORMS WILL IMPACT SOUTHERN LIBERTY...MCINTOSH AND SOUTHEASTERN LONG COUNTIES THROUGH 515 PM EDT... AT 429 PM EDT...NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A LINE OF STRONG THUNDERSTORMS CAPABLE OF PRODUCING LOCALLY STRONG WINDS OF 40 TO 50 MPH. THESE STORMS WERE LOCATED ALONG A LINE EXTENDING FROM SOUTH NEWPORT TO COX...OR ALONG A LINE EXTENDING FROM 14 MILES EAST OF TIBET TO 9 MILES SOUTH OF TIBET...MOVING EAST AT 20 MPH. AREAS IN AND AROUND HUXFORD...SOUTH NEWPORT...TOWNSEND...COX... HALFMOON LANDING...DARIEN...RIDGEVILLE...ASHINTILLY...WILL BE IMPACTED THROUGH 515 PM EDT. PRECAUTIONARY/PREPAREDNESS ACTIONS... FREQUENT CLOUD-TO-GROUND LIGHTNING IS OCCURRING. POSTPONE OUTDOOR ACTIVITIES PROMPTLY. SEEK SHELTER INSIDE AN ENCLOSED BUILDING. &&
PRELIMINARY LOCAL STORM REPORT
NATIONAL WEATHER SERVICE CHARLESTON SC
435 PM EDT FRI JUL 31 2009
..TIME... ...EVENT... ...CITY LOCATION... ...LAT.LON...
..DATE... ....MAG.... ..COUNTY LOCATION..ST.. ...SOURCE....
..REMARKS..
0345 PM TSTM WND DMG 4 NNW CLAXTON 32.22N 81.92W
07/31/2009 EVANS GA LAW ENFORCEMENT
THE EVANS COUNTY WARNING POINT REPORTED THAT A TREE WAS
BLOWN DOWN ALONG HENDRIX BRIDGE ROAD.
0347 PM TSTM WND DMG 4 N CLAXTON 32.22N 81.89W
07/31/2009 EVANS GA LAW ENFORCEMENT
THE EVANS COUNTY WARNING POINT REPORTED THAT A TREE WAS
BLOWN DOWN ONTO A POWER LINE ALONG TELLIE AIKINS ROAD.
&&The Charleston,SC radar (KCLX), 46 km away, was scanning. The volume nearest the first event began at 20:55 UTC.
2 thunderstorm wind, 1 lightning. Local standard time, as filed.
Law Enforcement reported that lightning started a structure fire on Lakewood Drive near Walterboro, South Carolina.
The Colleton County Warning Point reported that a power line was blown down onto Round O Road due by strong thunderstorm winds in Round O, South Carolina.
Law Enforcement reported a tree down on Coosaw Scenic Highway near Old House, 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, July 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 2026-09-24. Each event’s entry at NCEI: 190536, 190538, 190539.