Afternoon thunderstorms formed along the seabreeze and outflow boundaries over southeast South Carolina. The collapsing storms produced several reports of downed trees.
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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.
Afternoon thunderstorms formed along the seabreeze and outflow boundaries over southeast South Carolina. The collapsing storms produced several reports of downed trees.
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 17, 9:30 AM EST, 2 hours 52 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON SC 1030 AM EDT TUE JUL 17 2012 .SYNOPSIS... ATLANTIC HIGH PRESSURE WILL EXTEND ACROSS THE REGION THROUGH LATE WEEK. A COLD FRONT WILL STALL OUT NEARBY THIS WEEKEND LEADING TO UNSETTLED CONDITIONS...THEN DISSIPATE EARLY NEXT WEEK. && .NEAR TERM /UNTIL 6 PM THIS EVENING/... A WEAK LEE SURFACE TROUGH REMAINS INLAND WHILE A CLOSED UPPER LOW CONTINUES TO TO SPIN OVER NORTHERN FLORIDA. A STRONGER CAP EXISTS TODAY COMPARED WITH YESTERDAY...AS EVIDENT IN THE LACK OF CUMULUS FIELD THUS FAR. WE ARE APPROACHING OUR CONVECTIVE TEMPS /MID 80S/ SO A CU FIELD WILL LIKELY BEGIN TO FORM PRIOR TO NOON. AN EXTENSIVE CIRRUS SHIELD ASSOCIATED WITH THE UPPER LOW IS SPREADING INTO SOUTHEAST GA WHICH COULD SLIGHTLY LIMIT SURFACE HEATING BUT IN GENERAL WE STILL EXPECT LOWER 90S FOR HIGHS. MODIFIED KCHS AND KJAX SOUNDINGS YIELD APPROXIMATELY 3000 JOULES OF CAPE WITH DOWNDRAFT CAPE AROUND 1000 JOULES AND LIFTED INDEX OF -6C. MID-LEVEL LAPSE RATES ARE MARGINAL AND PRECIPITABLE WATER VALUES NOW EXCEED 2 INCHES SO WE ARE DEALING WITH A JUICY AIRMASS. ONCE THE SEABREEZE BEGINS TO MOVE INLAND DURING THE AFTERNOON WE EXPECTED ISOLATED TO SCATTERED SHOWERS/STORMS TO DEVELOP. THE BEST COVERAGE IS EXPECTED IN SOUTHEAST GA DUE TO LOWER HEIGHTS ALOFT. ISOLATED SEVERE THUNDERSTORM POTENTIAL TODAY...PRIMARILY FROM WET MICROBURSTS. && .SHORT TERM /6 PM THIS EVENING THROUGH FRIDAY/... BOUNDARIES SHOULD KEEP SCATTERED INLAND CONVECTION GOING FOR A WHILE THIS EVENING. A FEW MODELS SUGGEST TSTMS COULD MERGE INTO CLUSTERS AND THIS MAY PRODUCE SOME SPOTTY HEAVY RAINS OVER SOME INLAND AREAS GIVEN THE MOISTURE PROFILES. WE RAISED SOME INLAND POPS TO CHANCE THEN ALLOW POPS TO DIMINISH OVERNIGHT. A FEW SHOWERS AND TSTMS COULD REDEVELOP OVERNIGHT ALONG COASTAL AREAS AND WE MAINTAINED SOME OVERNIGHT SLIGHT CHANCES. WIDESPREAD DEBRIS CLOUDS ARE EXPECTED TO SLOWLY THIN LATE. LOWS IN THE 70S. MID/UPPER-LEVEL LOW PRESSURE ACROSS THE AREA WILL WEAKEN BUT GENERAL TROUGHING WILL PERSIST THROUGH FRIDAY. AT THE SURFACE...A TROUGH OF LOW PRESSURE WILL REMAIN IN PLACE THROUGH THE PERIOD. DEEP MOISTURE AND TEMPERATURES IN THE LOWER TO MID 90S WILL PROVIDE PLENTY OF INSTABILITY TO SUPPORT SCATTERED SHOWERS AND THUNDERSTORMS EACH DAY...MAINLY IN THE AFTERNOON AND EVENING AWAY FROM THE IMMEDIATE COAST. HOWEVER...AN INCREASING SW/W LOW-LEVEL FLOW THURSDAY AND FRIDAY WILL YIELD DECENT CHANCES EVEN AT THE COAST. PRECIPITABLE WATER VALUES UP NEAR 2.4 INCHES WILL PROMOTE SOME HEAVY RAINFALL IN THE STRONGER STORMS. TEMPERATURES WILL BE SLIGHTLY ABOVE NORMAL THIS PERIOD. && .LONG TERM /FRIDAY NIGHT THROUGH MONDAY/... A SHARPENING TROUGH TO THE NORTH LATE IN THE WEEK WILL HELP SLOWLY PUSH A COLD FRONT SOUTH TOWARD THE AREA THROUGH THE WEEKEND BUT IT SHOULD STALL OUT AND REMAIN NORTH OF THE AREA...AS CLIMATOLOGY WOULD SUGGEST. HOWEVER...PLENTY OF DEEP MOISTURE AND INSTABILITY WILL BE FOUND SOUTH OF THE FRONT ACROSS THE LOCAL AREA WHICH WILL MAKE FOR UNSETTLED CONDITIONS WITH HIGHER THAN NORMAL RAIN CHANCES...AND SOME LOCALIZED HEAVY RAINFALL. LINGERING DEEP TROUGHING WILL RETURN EARLY NEXT WEEK WITH MORE TYPICAL RAIN CHANCES FOR THIS TIME OF YEAR. HIGH TEMPERATURES WILL BE HELD DOWN CLOSER TO NORMAL LATE IN THE WEEK BEFORE POSSIBLY RISING ABOVE NORMAL EARLY NEXT WEEK. && .AVIATION /14Z TUESDAY THROUGH SATURDAY/... VFR WILL DOMINATE AT KCHS/KSAV THROUGH 12Z WED. A LAND BREEZE WILL KEEP SHOWERS AND TSTMS NEAR THE COAST THIS MORNING WITH CONVECTION TRANSITIONING INLAND THIS AFTERNOON AS THE SEA BREEZE KICKS IN. PLAN TO MAINTAIN THE VCTS AT BOTH TERMS BEGINNING AT 18Z WITH CB/S AS WELL. CANNOT RULE OUT AN EVENING TSTM BUT OVERALL WE THINK DEEP MOISTURE WILL LIKELY JUST RESULT IN DEBRIS CLOUDINESS. EXTENDED AVIATION OUTLOOK...A WEAK TROUGH OF LOW PRESSURE WILL ENHANCE CHANCES FOR SHOWERS AND TSTMS THROUGH THE WEEK. && .MARINE... NOT MUCH CHANGE TO THE OVERALL SCHEME OF THE COASTAL WATERS FORECAST THIS MORNING. WINDS VEERING A BIT MORE OFFSHORE THIS MORNING THEN BACKING WITH INLAND TROUGH AND SEA BREEZE. A BIT OF A SW SURGE TONIGHT BUT SPEEDS SHOULD GENERALLY REMAIN 15 KT OR LESS. SEAS 2 TO 3 FT THROUGH TONIGHT ON AVERAGE. WEDNESDAY THROUGH SUNDAY...AN INLAND TROUGH OF LOW PRESSURE ALONG WITH ATLANTIC HIGH PRESSURE WILL COMBINE TO BRING SLIGHTLY HIGHER WINDS/SEAS TO THE AREA FOR MID WEEK. SMALL CHANCES OF ADVISORY CONDITIONS BEING MET...ESPECIALLY IN CHS HARBOR AS WINDS ARE ENHANCED BY THE AFTERNOON SEA BREEZE. WINDS/SEAS SHOULD LOWER A BIT TOWARD THE END OF THE WEEK HOWEVER AS A WEAK COLD FRONT APPROACHES FROM THE NORTH AND WEAK LOW PRESSURE DEVELOPS ALONG IT ULTIMATELY LEADING TO A WEAKENING PRESSURE GRADIENT. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...NONE. SC...NONE. MARINE...NONE. && SYNOPSIS... NEAR TERM...JRL SHORT TERM...RJB/ LONG TERM...RJB AVIATION...RJB MARINE...RJB/
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
The Charleston,SC radar (KCLX), 41 km away, was scanning. The volume nearest the first event began at 17:22 UTC.
7 thunderstorm wind. Local standard time, as filed.
Dispatch Center reported a tree down at SC Highway 3 and Cohens Bluff Road.
SC Highway Patrol reported a tree down on Highway 21 near the SC Department of Transportation.
Dispatch Center reported a tree down at on Highway 21 at Risher Road.
Dispatch Center reported several trees down at on Highway 21 at Quarters Drive.
Dispatch Center reported a car that hit a downed tree down on Jefferies Blvd in Walterboro.
Dispatch Center reported a tree down at the intersection of Highway 462 and Glover Road. Pea size hail was also reported.
Dispatch Center reported a tree on a car on Mungin Road. No injuries.
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, July 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: 401634, 401635, 401636, 401637, 401638, 401640, 401641.