A weak surface trough east of the Appalachians combined with a sea breeze initiated scattered thunderstorms over SE SC.
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 weak surface trough east of the Appalachians combined with a sea breeze initiated scattered thunderstorms over SE SC.
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 Apr 4, 5:07 PM EST, 23 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE CHARLESTON SC 607 PM EDT WED APR 4 2012 .SYNOPSIS... A BACKDOOR COLD FRONT APPROACHES FROM THE NORTH TONIGHT AND THURSDAY. THE FRONT WILL EVENTUALLY MOVE THROUGH THE AREA THURSDAY NIGHT AND EARLY FRIDAY...AS A WAVE OF LOW PRESSURE DEVELOPS ON THE FRONT AND DEEPENS OVER THE GULF STREAM. COOLER HIGH PRESSURE WILL THEN BUILD BEHIND THE FRONT FOR THE EASTER WEEKEND. A SECONDARY COLD FRONT WILL MOVE THROUGH SUNDAY NIGHT...WITH YET ANOTHER COLD FRONT TO CROSS THE AREA TUESDAY. && .NEAR TERM /UNTIL 6 AM THURSDAY MORNING/... TSTMS ARE SLOWLY ORGANIZING INTO A LINE NEAR WALTERBORO. THIS LINE WILL INTERSECT THE SEABREEZE WITHIN THE NEXT 1-2 HOURS...POSSIBLY YIELDING A STRONG OR BRIEFLY SEVERE TSTM WITHIN THE CHARLESTON TRI-COUNTY AREA. ELSEWHERE...THE RISK FOR AN ISOLATED SHOWER OR TSTM WILL CONTINUE...ALTHOUGH PROSPECTS FOR MEASURABLE RAINFALL ARE LOW. OPTED TO LOWER CLOUD COVER THIS EVENING WITH THE LACK OF SIGNIFICANT CONVECTIVE DEBRIS CLOUDINESS FROM ONGOING ACTIVITY. SATELLITE ALSO SHOWS CIRRUS BLOW OFF FROM THE LARGE MESOSCALE CONVECTIVE SYSTEM MOVING THROUGH THE GULF OF MEXICO THINNING. MAY HAVE TO ADJUST CLOUD COVER DOWN FROM MIDNIGHT ON FOR THE LATE EVENING UPDATE. && .SHORT TERM /6 AM THURSDAY MORNING THROUGH SATURDAY/... THURSDAY...A POTENT UPPER LOW WILL TRACK EAST ACROSS THE LOWER MISSISSIPPI AND TENNESSEE VALLEYS ON THURSDAY...DAMPENING THE WEAK UPPER RIDGING ACROSS THE SOUTHEAST STATES. AT THE SURFACE...A BACKDOOR COLD FRONT WILL HAVE DESCENDED TO APPROXIMATELY THE NORTH CAROLINA/SOUTH CAROLINA BORDER BY THURSDAY MORNING. ABUNDANT UPPER LEVEL ENERGY ALONGSIDE AND DOWNSTREAM OF THE UPPER LOW WILL ASSIST IN THE DEVELOPMENT OF A SURFACE WAVE ALONG THE LINGERING COLD FRONT. NOTABLE DIFFERENCES IN NUMERICAL MODEL EVOLUTION OF THESE SYNOPTIC SCALE FEATURES HAS CREATED SOME UNCERTAINTY IN FORECAST DETAILS FOR THURSDAY...ESPECIALLY CONCERNING ORGANIZED SEVERE WEATHER POTENTIAL. 12Z GFS SOLUTION TAKES THE BACKDOOR COLD FRONT FARTHER SOUTH INTO THE FORECAST AREA THURSDAY AFTERNOON...WHILE MAINTAINING A DEEPER UPPER LEVEL SYSTEM THROUGH THURSDAY NIGHT. 12Z NAM AND ECMWF SOLUTIONS ARE IN BETTER AGREEMENT...AND ALTHOUGH HAVE PREFERRED NOT TO MAKE SWEEPING CHANGES TO THE ONGOING FORECAST AT THIS TIME...HAVE GENERALLY LEANED TOWARD THESE MODEL RUNS. TWO MAIN AREAS OF CONVECTION COULD POTENTIALLY IMPACT THE FORECAST AREA BY THURSDAY AFTERNOON/EVENING...ONE COMPLEX ORIGINATING ALONG THE GULF COAST STATES COINCIDENT WITH THE UPPER LOW...AND ANOTHER AREA OF CONVECTION CONCENTRATED ALONG THE LINGERING BOUNDARY TO THE NORTH. DEEP MOISTURE WILL BE INCREASING ACROSS THE SOUTHEAST STATES AHEAD OF THE APPROACHING SYSTEM...AND HAVE INDICATED STEADILY INCREASING SHOWER/THUNDERSTORM CHANCES PEAKING IN THE 50 TO 60 PERCENT RANGE LATE THURSDAY INTO THURSDAY NIGHT. WILL GENERALLY INDICATE HIGHEST POPS ACROSS THE NORTHERN HALF OF THE FORECAST AREA CLOSEST TO ENHANCED CONVERGENCE AND FORCING NEAR THE BACKDOOR FRONT. HIGH TEMPERATURES WILL BE A FEW DEGREES COOLER THURSDAY AFTERNOON DUE TO INCREASED CLOUD COVER AND SCATTERED TO NUMEROUS STORMS. STORM PREDICTION CENTER HAS PLACED THE FORECAST AREA WITHIN A 5 PERCENT RISK FOR ORGANIZED SEVERE WEATHER ON THURSDAY...AS THE DEGREE OF INSTABILITY REMAINS IN SOME QUESTION. MANY OF THE SEVERE PARAMETERS ARE HIGHLY DEPENDENT ON WHICH MODEL SOLUTION IS PREFERRED...WITH THE GFS GENERALLY MORE AGGRESSIVE. HOWEVER IT HAS BEEN NOTED THAT BOTH GFS AND NAM HAVE ARRIVED WITH MORE MARGINAL LOW LEVEL INSTABILITY FOR THURSDAY...POSSIBLY DUE TO THE EFFECTS OF CLOUD COVER AND EARLIER CONVECTION. IN ADDITION...LOW LEVEL WIND FIELDS ARE SOMEWHAT UNIMPRESSIVE EVEN IN THE MORE AGGRESSIVE GFS SOLUTION. ISOLATED THUNDERSTORMS BECOMING STRONG TO SEVERE REMAIN A POSSIBILITY REGARDLESS...HOWEVER COVERAGE AND TIMING LEND MUCH UNCERTAINTY. AS A RESULT...REMAIN HESITANT TO ADD SEVERE WORDING TO THE HAZARDOUS WEATHER OUTLOOK FOR THURSDAY AND ALLOW SUBSEQUENT FORECAST SHIFTS TO REASSESS MODEL CONSISTENCY. THURSDAY NIGHT/FRIDAY...THE UPPER LOW AND ASSOCIATED SURFACE WAVE WILL STEADILY PROGRESS DIRECTLY OVER THE FORECAST AREA THURSDAY NIGHT AND SLIP OFFSHORE BY FRIDAY MORNING. THESE DEPARTING FEATURES WILL PULL THE LINGERING BACKDOOR FRONT THROUGH THE AREA LATE MORNING/EARLY AFTERNOON FRIDAY. HAVE INDICATED RAIN CHANCES DECREASING FROM SOUTHWEST TO NORTHEAST AFTER MIDNIGHT EARLY FRIDAY MORNING...WHILE MAINTAINING SOLID CHANCE POPS THROUGH THE LATE MORNING HOURS TO ACCOUNT FOR RESIDUAL DEEP MOISTURE AND CONVERGENCE WITH THE FRONTAL PASSAGE. IF THE FRONT IS SLOWER IN PROGRESSING SOUTH/SOUTHEAST...A FEW THUNDERSTORMS COULD DEVELOP SOUTH OF INTERSTATE 16 IN SOUTHEAST GEORGIA. OTHERWISE JUST LIGHT RAIN OR SHOWERS ARE EXPECTED FOR PART OF THE DAYTIME HOURS ON FRIDAY. IN ADDITION...A TIGHT PRESSURE GRADIENT BETWEEN THE SURFACE LOW PRESSURE MOVING INTO THE ATLANTIC LOW AND HIGH PRESSURE BUILDING FROM THE GREAT LAKES WILL RESULT IN A BREEZY TO WINDY DAY...WITH NORTHERLY WINDS OF 15 TO 25 MPH AND GUSTY. CONSIDERABLY COOLER AIR WILL ADVECT INTO THE REGION WITHIN NORTHERLY FLOW BEHIND THE FRONT...AND EXPECT HIGH TEMPERATURES TO BE SUPPRESSED IN THE MID 60S NORTH TO THE LOWER 70S SOUTH. FRIDAY NIGHT/SATURDAY...PERSISTENT COOL ADVECTION WITHIN BUILDING CANADIAN HIGH PRESSURE WILL RESULT IN CONSIDERABLY LOWER TEMPERATURES FRIDAY NIGHT. UNDER CLEARING SKIES...EXPECT TEMPERATURES TO FALL INTO THE MID TO UPPER 40S FOR MOST LOCATIONS. SURFACE HIGH PRESSURE WILL THEN CONTINUE TO SLIP OVER THE SOUTHEAST STATES ON SATURDAY. AFTERNOON TEMPERATURES WILL BE A FEW DEGREES WARMER THAN FRIDAY...YET STILL REMAIN COOL IN COMPARISON TO CONDITIONS DURING THE PAST FEW WEEKS. EXPECT HIGHS TO GENERALLY REACH THE LOWER 70S UNDER NORTHEAST FLOW AND CLEAR SKIES. && .LONG TERM /SATURDAY NIGHT THROUGH WEDNESDAY/... THE MEAN TROUGH WILL PERSIST IN THE EASTERN UNITED STATES THROUGH THE PERIOD...WITH A SERIES OF COLD FRONTS TO CROSS THE AREA WITHIN THE NW FLOW ALOFT. THERE IS NO CHANCE OF ANY RAINFALL WITH THE FIRST FRONT SUNDAY NIGHT...WITH MAYBE A SMALL CHANCE WITH ANOTHER FRONT TUESDAY. FOR NOW WE/LL CARRY A DRY FORECAST THROUGH THE MIDDLE OF NEXT WEEK WITH PWATS WELL UNDER AN INCH TO OCCUR. PLENTY OF DAYTIME INSOLATION AND DOWNSLOPE FLOW OFF THE MOUNTAINS WILL BOOST READINGS UP NEAR OR ABOVE SEASONAL NORMS...WHILE NIGHTTIME COOL ADVECTION BEHIND EACH FRONT ALLOWS FOR MINIMUM VALUES TO FALL BELOW NORMAL THROUGH THE PERIOD. && .AVIATION /22Z WEDNESDAY THROUGH MONDAY/... CUMULUS HAS BEEN A BIT SLOWER TO POP THIS AFTERNOON BUT WE ARE BEGINNING TO SEE TOWERING CU AND A SHOWER OR TWO AS OF THE LATEST RADAR SCAN. THE BEST CONVECTIVE COVERAGE IS EXPECTED INLAND FROM THE TERMINALS CLOSER TO THE LEE TROUGH SO WE DID NOT INCLUDE ANY TSRA AT EITHER SITE WITH THE 18Z TAFS. WE WILL NEED TO MONITOR TRENDS BEFORE CONSIDERING ADDING THUNDER. DIURNALLY-DRIVEN SHOWERS AND THUNDERSTORMS WILL DISSIPATE AFTER SUNSET. A FEW SHOWERS OR STORMS COULD LINGER OVERNIGHT AS A BACKDOOR FRONT DROPS IN FROM THE NORTH BUT COVERAGE WILL PROBABLY BE LIMITED. MVFR CEILINGS CANNOT BE COMPLETELY RULED OUT LATE TONIGHT...HOWEVER PROBABILISTIC GUIDANCE SHOWS LOWER THAN A 20 PERCENT CHANCE OF THIS OCCURRING. EXTENDED AVIATION OUTLOOK...MVFR OR LOWER CONDITIONS LIKELY LATE THURSDAY INTO FRIDAY AS A FRONTAL SYSTEM IMPACTS THE AREA. VFR WEATHER WILL RETURN LATE FRIDAY THROUGH SUNDAY. && .MARINE... TONIGHT...WSW WINDS WILL INCREASE TONIGHT AS A BACKDOOR FRONT APPROACHES FROM THE NORTH AND A SHORTWAVE MOVES THROUGH FROM THE WEST. WINDS WILL APPROACH 20 KT LATE TONIGHT ON THE OUTER WATERS BUT THE OFFSHORE FETCH WILL NOT RESULT IN AN APPRECIABLE BUILDING OF SEAS. THURSDAY THROUGH MONDAY...A GENERAL SOUTHWEST FLOW ON THURSDAY COULD BECOME MORE VARIABLE ACROSS NORTHERN PORTIONS OF THE MARINE ZONES...AS A BACKDOOR FRONT LINGERS ALONG THE NORTHERN PERIPHERY OF THE FORECAST AREA. MARINE CONDITIONS WILL THEN DETERIORATE THURSDAY NIGHT INTO FRIDAY AS THE FRONT IS PULLED THROUGH THE REGION EARLY FRIDAY. A TIGHTENED GRADIENT WILL DEVELOP IN THE WAKE OF THE FRONT...AS LOW PRESSURE DEEPENS OVER THE GULF STREAM AND HIGH PRESSURE BUILDS FROM THE NORTH. WINDS AND SEAS WILL SURGE ACCORDINGLY...WITH SOLID SMALL CRAFT ADVISORY CONDITIONS LIKELY ACROSS ALL MARINE ZONES ON FRIDAY. HAVE MADE LITTLE CHANGES TO THE ONGOING FORECAST...INDICATING NORTH TO NORTHEAST WINDS PEAKING AROUND 20 TO 30 KT...WITH SOME POTENTIAL FOR MARGINAL GALES TO OCCUR ACROSS THE OUTER EDGES OF THE CHARLESTON COUNTY WATERS AND THE OFFSHORE GEORGIA ZONES. SEAS WILL BUILD AS HIGH AS 5 TO 7 FT WITHIN 20 NM OF THE COAST AND UP NEAR 9 OR 10 FT ACROSS THE OUTER GEORGIA WATERS. MARINE CONDITIONS WILL SLOWLY IMPROVE SATURDAY AFTERNOON...AS SURFACE HIGH PRESSURE SHIFTS OVER THE AREA THROUGH SUNDAY. A SECONDARY COLD FRONT WILL CROSS THE WATERS SUNDAY NIGHT...AND WITH INCREASING COLD ADVECTION WE MIGHT BE LOOKING AT MARGINAL SCA/S AGAIN FOR MONDAY NIGHT INTO EARLY TUESDAY. && .TIDES/COASTAL FLOODING... THE COMBINATION OF THE PERIGEAN SPRING TIDE LATE THIS WEEK AND MODERATE TO STRONG NORTH AND NE WINDS WILL LEAD TO POSITIVE TIDAL DEPARTURES FRIDAY. AS A RESULT...THERE IS THE RISK OF AT LEAST SHALLOW COASTAL FLOODING AROUND THE TIME OF THE EVENING HIGH TIDE. WITH HIGHER THAN NORMAL SEAS TO OCCUR WE ALSO ANTICIPATE MINOR FLOODING PROBLEMS. RIP CURRENTS...THE SAME CONDITIONS THAT MAY CAUSE SHALLOW COASTAL FLOODING/EROSION WILL LEAD TO AN ELEVATED RISK OF RIP CURRENTS AT AREA BEACHES FRIDAY AND AGAIN ON SATURDAY. && .CHS WATCHES/WARNINGS/ADVISORIES... GA...NONE. SC...NONE. MARINE...NONE. && SYNOPSIS... NEAR TERM... SHORT TERM...79 LONG TERM... AVIATION...JRL MARINE...RJB/79 TIDES/COASTAL FLOODING...
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE CHARLESTON SC 337 PM EDT WED APR 4 2012 AMZ330-GAZ087-088-099>101-114>116-118-137-138-140-SCZ040-042>045-047- 052-051945- CHARLESTON HARBOR-JENKINS-SCREVEN-CANDLER-BULLOCH-EFFINGHAM-TATTNALL- EVANS-INLAND BRYAN-INLAND CHATHAM-LONG-INLAND LIBERTY- INLAND MCINTOSH-ALLENDALE-HAMPTON-INLAND COLLETON-DORCHESTER- INLAND BERKELEY-INLAND JASPER-TIDAL BERKELEY- 337 PM EDT WED APR 4 2012 THIS HAZARDOUS WEATHER OUTLOOK IS FOR ATLANTIC COASTAL WATERS...SOUTHEAST GEORGIA AND SOUTHEAST SOUTH CAROLINA. .DAY ONE...THIS AFTERNOON AND TONIGHT. SEVERE THUNDERSTORMS...SCATTERED THUNDERSTORMS ARE EXPECTED LATE THIS AFTERNOON INTO THE EARLY EVENING HOURS. THERE IS A CHANCE THAT A FEW STORMS COULD BRIEFLY BECOME SEVERE. THE MAIN THREAT WILL BE FROM LARGE HAIL...AND TO A LESSER EXTENT DAMAGING STRAIGHT LINE WINDS. .DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY. NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME. .SPOTTER INFORMATION STATEMENT... SPOTTERS ARE ENCOURAGED TO REPORT SEVERE WEATHER TO THE NATIONAL WEATHER SERVICE IN CHARLESTON SC. GAZ117-119-139-141-SCZ048>051-051945- COASTAL BRYAN-COASTAL CHATHAM-COASTAL LIBERTY-COASTAL MCINTOSH- BEAUFORT-COASTAL COLLETON-CHARLESTON-COASTAL JASPER- 337 PM EDT WED APR 4 2012 THIS HAZARDOUS WEATHER OUTLOOK IS FOR SOUTHEAST GEORGIA AND SOUTHEAST SOUTH CAROLINA. .DAY ONE...THIS AFTERNOON AND TONIGHT. SEVERE THUNDERSTORMS...SCATTERED THUNDERSTORMS ARE EXPECTED LATE THIS AFTERNOON INTO THE EARLY EVENING HOURS. THERE IS A CHANCE THAT A FEW STORMS COULD BRIEFLY BECOME SEVERE. THE MAIN THREAT WILL BE FROM LARGE HAIL...AND TO A LESSER EXTENT DAMAGING STRAIGHT LINE WINDS. .DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY. TIDES/COASTAL FLOODING...THE COMBINATION OF MODERATE TO STRONG NORTHEAST WINDS AND THE UPCOMING SPRING TIDE MAY RESULT IN SHALLOW COASTAL FLOODING FRIDAY AND SATURDAY EVENINGS. A COASTAL FLOOD ADVISORY MAY BE REQUIRED. RIP CURRENTS...MODERATE TO STRONG WINDS...LARGER THAN NORMAL BREAKING WAVES...AND THE SPRING TIDE WILL RESULT IN AN ELEVATED RISK OF RIP CURRENTS AT AREA BEACHES FRIDAY AND SATURDAY. .SPOTTER INFORMATION STATEMENT... SPOTTERS ARE ENCOURAGED TO REPORT SEVERE WEATHER TO THE NATIONAL WEATHER SERVICE IN CHARLESTON SC. AMZ350-352-354-374-051945- 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- 337 PM EDT WED APR 4 2012 THIS HAZARDOUS WEATHER OUTLOOK IS FOR ATLANTIC COASTAL WATERS. .DAY ONE...THIS AFTERNOON AND TONIGHT. NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME. .DAYS TWO THROUGH SEVEN...THURSDAY THROUGH TUESDAY. NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME. .SPOTTER INFORMATION STATEMENT... SPOTTERS ARE ENCOURAGED TO REPORT SEVERE WEATHER TO THE NATIONAL WEATHER SERVICE IN CHARLESTON SC.
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE CHARLESTON SC
557 PM EDT WED APR 4 2012
SCZ043-044-042230-
DORCHESTER-INLAND COLLETON-
557 PM EDT WED APR 4 2012
...STRONG THUNDERSTORMS WILL IMPACT PORTIONS OF DORCHESTER AND
COLLETON COUNTIES THROUGH 630 PM EDT...
AT 553 PM EDT...NATIONAL WEATHER SERVICE METEOROLOGISTS DETECTED
STRONG THUNDERSTORMS...ALONG A LINE EXTENDING FROM PADGETTS TO
HENDERSONVILLE...MOVING EAST AT 35 MPH.
SOME LOCATIONS THAT WILL BE AFFECTED INCLUDE...
CANADYS...COTTAGEVILLE...GREEN POND...HENDERSONVILLE...INDIAN
FIELD...JACKSONBORO...PADGETTS...REEVESVILLE...RITTER...ROUND O...
RUFFIN...SAINT GEORGE...SMOAKS...WALTERBORO...WHITE HALL AND
WILLIAMS...
PREPARE NOW FOR THE FOLLOWING HAZARDS...
GUSTY WINDS OF 40 TO 50 MPH...
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.
&&
LAT...LON 3324 8053 3286 8032 3286 8040 3281 8040
3279 8043 3275 8045 3272 8072 3308 8090
3310 8089 3313 8090 3321 8075
TIME...MOT...LOC 2157Z 268DEG 31KT 3308 8085 3275 8070The Charleston,SC radar (KCLX), 67 km away, was scanning. The volume nearest the first event began at 22:31 UTC.
4 thunderstorm wind. Local standard time, as filed.
SC Highway Patrol reported a tree down on Pierce and McDaniel Town Roads.
SC Highway Patrol reported a tree down at Tupperway Drive and Boone Hill Road.
Charleston Media reported a tree down in Knightsville.
Several trees blown down in the Liberty Hall subdivision.
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, April 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: 379069, 379071, 379072, 379073.