A lingering front over SE Ga combined with passing upper level impulses triggered a few strong to severe storms over an unstable airmass.
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 JAX wrote it up.
A lingering front over SE Ga combined with passing upper level impulses triggered a few strong to severe storms over an unstable airmass.
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 Jacksonville, FL wrote its last area forecast discussion before the first event at Aug 12, 2:05 PM EST, 2 hours 20 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE JACKSONVILLE FL 305 PM EDT MON AUG 12 2013 ...HIGH HEAT INDICES CONTINUE THROUGH WEDNESDAY... ...INCREASING RAIN CHANCES BEGINNING THURSDAY... .CURRENTLY... AFTERNOON SURFACE ANALYSIS DEPICTS A RATHER STAGNANT WEATHER PATTERN...WITH SURFACE RIDGING (1021 MILLIBARS) CENTERED OVER THE FLORIDA PANHANDLE. ALOFT...STACKED RIDGING REMAINS CENTERED OVER OUR REGION. A LARGELY SUBSIDENT AIR MASS BENEATH THIS RIDGE HAS SUPPRESSED CONVECTIVE DEVELOPMENT OVER MUCH OF THE REGION THUS FAR...WITH ONLY ISOLATED SHOWERS DEVELOPING EARLY THIS AFTERNOON ALONG THE PERIPHERY OF THE RIDGE NEAR THE ALTAMAHA RIVER AND ALONG THE ATLANTIC SEABREEZE AS IT MOVES WESTWARD TOWARDS INTERSTATE 95. TEMPERATURES THIS AFTERNOON ARE SOARING INTO THE MID 90S INLAND...AND COUPLED WITH DEWPOINTS IN THE LOW TO MID 70S...HEAT INDICES AT INLAND LOCATIONS ARE APPROACHING 105 DEGREES. THE SEABREEZE HAS MOVED PAST MOST COASTAL SENSORS...WHERE TEMPERATURES ARE STILL NEAR 90 DEGREES WITH DEWPOINTS IN THE MID AND UPPER 70S. .NEAR TERM (THIS AFTERNOON THROUGH TUESDAY)... THE EAST COAST SEABREEZE IS INITIATING ISOLATED CONVECTION OVER NORTHEAST FL AS THIS BOUNDARY MOVES OVER THE I-95 CORRIDOR. MESOSCALE BOUNDARY COLLISIONS SHOULD RESULT IN AT LEAST WIDELY SCATTERED COVERAGE ALONG AND WEST OF I-95 IN NORTHEAST FL AND SOUTHEAST GA BY 21Z...WITH ACTIVITY POSSIBLY DEVELOPING ALONG HIGHWAY 301 IN NORTHEAST/NORTH CENTRAL FL TOWARDS 22Z-23Z. RIDGING OVERHEAD WILL RESULT IN SLOW EAST OR SOUTHEASTWARD STORM MOTION...AND DRY AIR IN THE MID LEVELS SHOULD AID IN DEVELOPMENT OF A FEW STRONGER PULSE STORMS THAT COULD PRODUCE LOCALLY GUSTY WINDS AND FREQUENT LIGHTNING STRIKES. FOR AREAS DEVOID OF CONVECTION...HEAT INDICES AROUND 105 DEGREES WILL CONTINUE THROUGH THE LATE AFTERNOON HOURS. A FEW STORMS COULD MOVE INTO COASTAL LOCATIONS EARLY THIS EVENING...WITH ACTIVITY PERHAPS LINGERING OVER THE OKEFENOKEE SWAMP AND COASTAL SOUTHEAST GA THROUGH MIDNIGHT. OTHERWISE...EXPECT MID AND HIGH ALTITUDE DEBRIS CLOUDS TO DISSIPATE OVERNIGHT...WHICH SHOULD LEAD TO ANOTHER GOOD NIGHT FOR VIEWING THE PEAK OF THE PERSEID METEOR SHOWER. SEASONABLY MUGGY CONDITIONS WILL CONTINUE...AS LOWS RANGE FROM THE MID 70S INLAND TO NEAR 80 AT THE COAST. STACKED RIDGING WILL BEGIN TO SHIFT SOUTHWARD ON TUESDAY AS A FRONTAL BOUNDARY CURRENTLY OVER THE OHIO VALLEY/MID-ATLANTIC STATES SAGS INTO THE SOUTHEASTERN STATES. AN OFFSHORE WIND REGIME WILL MAINTAIN HOT AND HUMID CONDITIONS REGION-WIDE...AS SEA BREEZE DEVELOPMENT MAY BE DELAYED UNTIL THE LATE AFTERNOON HOURS. HIGH TEMPERATURES WILL ONCE AGAIN CLIMB INTO THE MID/UPPER 90S INLAND...WITH LOWER 90S AT THE COAST. HEAT INDICES MAY ONCE AGAIN FLIRT WITH ADVISORY CRITERIA...BUT SHOULD GENERALLY REMAIN IN THE 104-108 DEGREE RANGE. DEEPER MOISTURE WILL BEGIN TO SHIFT TOWARDS THE ALTAMAHA BASIN BY THE AFTERNOON...AND WE INDICATED CHANCE POPS OVER INTERIOR SOUTHEAST GA AFTER 18Z...WITH WIDELY SCATTERED CONVECTION AGAIN EXPECTED TO INITIATE ALONG THE EAST COAST SEABREEZE ALONG THE I-95 CORRIDOR DURING THE LATE AFTERNOON HOURS. CONVECTION SHOULD FIZZLE TOWARDS SUNSET...WITH ACTIVITY POSSIBLY LINGERING INTO THE EVENING OVER INTERIOR SOUTHEAST GA. .SHORT TERM (TUESDAY NIGHT THROUGH THURSDAY NIGHT)... STALLED FRONTAL BOUNDARY ORIENTED FROM THE SW TO NE ACROSS SE GA WILL BE THE FOCUS FOR CONVECTIVE DEVELOPMENT DURING THE MID WEEK. THIS WILL KEEP HIGHEST CHANCES...BETWEEN 50-60 PERCENT...FOR PRECIP ACROSS OUR SE GEORGIA COUNTIES WHERE MOISTURE AXIS WILL BE FOUND. SOUTH OF THE BOUNDARY ACROSS NE FL CHANCES WILL BE SLIGHTLY LOWER...BETWEEN 30 TO 40 PERCENT WITH LIGHT WINDS OUT OF THE S TO SW. SHOWERS AND TSTORMS WILL SLOWLY DIMINISH EACH EVENING WITH LOW TEMPS DROPPING INTO THE LOW TO MID 70S. SLIGHT COOLING TREND WILL COMMENCE WITH TEMPS IN THE LOW/MID 90S WEDNESDAY THEN WITH INCREASED CLOUD COVER ON THURSDAY ALONG THE FRONTAL BOUNDARY SE GA WILL SEE MAX TEMPS IN THE UPPER 80S TO LOW 90S WITH NEAR NORMAL TEMPS IN THE LOW 90S ACROSS NE FL. .LONG TERM (FRIDAY THROUGH SUNDAY)... UPPER TROUGH WILL MAKE LITTLE PROGRESS ONCE IT REACHES THE MID MISSISSIPPI VALLEY KEEPING THE STATIONARY FRONTAL BOUNDARY PARKED ACROSS THE SE US THROUGH THE WEEKEND. LONG TERM MODELS SHOW A SURGE OF TROPICAL MOISTURE ACROSS N FLORIDA AND S GEORGIA BEGINNING ON FRIDAY ASSOCIATED WITH A SURFACE LOW THAT DEVELOPS OVER THE GULF OF MEXICO AND MOVES NE TOWARDS THE FL PANHANDLE. WITH PLENTY OF DEEP LAYER MOISTURE...PRECIP CHANCES WILL INCREASE TO NEAR 50 PERCENT ACROSS THE AREA EACH AFTERNOON THIS WEEKEND WITH A CONCERN BEING HEAVY RAINFALL WITH CONVECTION THAT DEVELOPS. A FEW STRONG THUNDERSTORMS WILL ALSO BE POSSIBLE. HIGH TEMPERATURES WILL BE NEAR NORMAL WITH UPPER 80S ALONG THE COAST AND LOW 90S INLAND AND LOWS IN THE LOW TO MID 70S. && .AVIATION... VFR CONDITIONS SHOULD PREVAIL THROUGH AT LEAST 20Z. SLOW MOVING THUNDERSTORMS SHOULD DEVELOP WEST OF THE TERMINAL BY 21Z- 22Z...WITH A SLOW DRIFT TOWARDS THE SOUTHEAST EXPECTED THROUGH 00Z. COVERAGE SHOULD REMAIN ISOLATED TO WIDELY SCATTERED...AND THUS INSERTED ONLY VICINITY SHOWERS AND THUNDERSTORMS IN THE TERMINAL FORECASTS THROUGH 00Z. A PERIOD OF MVFR VISIBILITIES IS POSSIBLE FROM 08Z-12Z AT VQQ AND GNV. LIGHT WEST TO NORTHWEST WINDS ARE EXPECTED FROM THE SURFACE UP THROUGH 10000 FT...WITH A SEA BREEZE DEVELOPING AND SHIFTING SURFACE WINDS TO A SOUTHEAST TO SOUTHERLY DIRECTION AT CRG AND SSI AFTER 19Z...AND AT JAX AND VQQ TOWARDS 21Z. LIGHT WINDS SHOULD PREVAIL AT GNV. && .MARINE... SOUTH TO SOUTHWESTERLY WINDS WILL PREVAIL AHEAD OF AN APPROACHING FRONTAL BOUNDARY. SCEC CONDITIONS WILL BE POSSIBLE EACH NIGHT TUESDAY THROUGH THURSDAY NIGHT WITH WINDS REACHING BETWEEN 15 TO 20 KTS. BEST CHANCES EXPECTED OVERNIGHT TUESDAY INTO WEDNESDAY. ISOLATED TO SCATTERED CONVECTION WILL BE POSSIBLE IN THE COASTAL WATERS TUESDAY NIGHT THROUGH THE WEEKEND AS THE BOUNDARY BECOMES STATIONARY ACROSS THE AREA. SEAS WILL REMAIN BETWEEN 2 TO 4 FEET FOR A MAJORITY OF THE WEEK. RIP CURRENTS: LOW RISK THROUGH AT LEAST FRIDAY. && .PRELIMINARY POINT TEMPS/POPS... AMG 75 93 74 92 / 30 30 30 60 SSI 78 93 77 90 / 30 40 40 50 JAX 75 96 76 93 / 30 30 30 40 SGJ 75 93 76 92 / 30 30 30 30 GNV 74 94 73 93 / 30 20 20 30 OCF 74 94 74 93 / 20 20 20 30 && .JAX WATCHES/WARNINGS/ADVISORIES... FL...NONE. GA...NONE. AM...NONE. && NELSON/MADEMOISELLE GUILLOTINE
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE JACKSONVILLE FL 425 AM EDT MON AUG 12 2013 AMZ450-452-454-470-472-474-FLZ020>025-030>033-035>038-040- GAZ132>136-149>154-162>166-130845- ALTAMAHA SOUND GA TO FERNANDINA BEACH FL OUT 20 NM- FERNANDINA BEACH TO ST AUGUSTINE FL OUT 20 NM- ST AUGUSTINE TO FLAGLER BEACH FL OUT 20 NM- ALTAMAHA SOUND GA TO FERNANDINA BEACH FL 20 NM TO 60 NM OFFSHORE- FERNANDINA BEACH TO ST AUGUSTINE FL 20 NM TO 60 NM OFFSHORE- ST AUGUSTINE TO FLAGLER BEACH FL 20 NM TO 60 NM OFFSHORE-HAMILTON- SUWANNEE-COLUMBIA-BAKER-NASSAU-DUVAL-UNION-BRADFORD-CLAY-ST JOHNS- GILCHRIST-ALACHUA-PUTNAM-FLAGLER-MARION-COFFEE-JEFF DAVIS-BACON- APPLING-WAYNE-ATKINSON-WARE-PIERCE-BRANTLEY-INLAND GLYNN- COASTAL GLYNN-ECHOLS-CLINCH-CHARLTON-INLAND CAMDEN-COASTAL CAMDEN- 425 AM EDT MON AUG 12 2013 ...HOT AND HUMID TODAY THROUGH WEDNESDAY WITH HEAT INDICES NEAR 104 TO 108... THIS HAZARDOUS WEATHER OUTLOOK IS FOR NORTHEAST FLORIDA... SOUTHEAST GEORGIA AND THE ADJACENT COASTAL WATERS. .DAY ONE...TODAY AND TONIGHT... HOT AND HUMID CONDITIONS CAN BE EXPECTED TODAY WITH HEAT INDICES 104 TO 108 DEGREES. ISOLATED TO BRIEFLY SCATTERED THUNDERSTORMS ARE EXPECTED THIS AFTERNOON AND EVENING...WITH THE GREATEST CHANCES OVER SOUTHEAST GEORGIA AND INTERIOR NORTHEAST FLORIDA. AN ISOLATED STRONG THUNDERSTORM WILL BE CAPABLE OF PRODUCING LOCALLY STRONG DOWNBURST WINDS...FREQUENT LIGHTNING...AND LOCALLY HEAVY RAINFALL. .DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY... HOT AND HUMID CONDITIONS CAN BE EXPECTED TUESDAY AND WEDNESDAY WITH 104 TO 108 HEAT INDICES POSSIBLE. ISOLATED TO SCATTERED AFTERNOON AND EVENING THUNDERSTORMS ARE ANTICIPATED TUESDAY...WITH AN INCREASE IN COVERAGE THE REST OF THE WEEK. A FEW STRONG THUNDERSTORMS ARE POSSIBLE EACH DAY WITH GUSTY WINDS AND FREQUENT LIGHTNING. LOCALLY HEAVY RAINFALL MAY BECOME MORE OF A CONCERN FRIDAY THROUGH SUNDAY AS A WEAK FRONTAL BOUNDARY LINGERS OVER PORTIONS OF SOUTHEAST GEORGIA. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS NOT REQUESTED AT THIS TIME. FOR ADDITIONAL INFORMATION...VISIT THE NATIONAL WEATHER SERVICE IN JACKSONVILLE WEBSITE ON THE INTERNET AT WEATHER.GOV/JAX.
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE JACKSONVILLE FL 1126 AM EDT MON AUG 12 2013 FLZ020>025-030>033-035>038-040-GAZ132>136-149>154-162>166-122100- ALACHUA-APPLING-ATKINSON-BACON-BAKER-BRADFORD-BRANTLEY- CAMDEN (COASTAL)-CAMDEN (INLAND)-CHARLTON-CLAY-CLINCH-COFFEE-COLUMBIA- DUVAL-ECHOLS-FLAGLER-GILCHRIST-GLYNN (COASTAL)-GLYNN (INLAND)-HAMILTON- JEFF DAVIS-MARION-NASSAU-PIERCE-PUTNAM-ST JOHNS-SUWANNEE-UNION-WARE- WAYNE- 1126 AM EDT MON AUG 12 2013 ...HEAT INDEX VALUES OF 104-108 DEGREES THIS AFTERNOON THROUGHOUT SOUTHEAST GEORGIA AND NORTHEAST FLORIDA... MOSTLY SUNNY SKIES AND LIGHT WEST TO NORTHWEST WINDS WILL ALLOW TEMPERATURES TO CLIMB INTO THE MID 90S BY THE EARLY AFTERNOON HOURS. THESE TEMPERATURES...COMBINED WITH DEWPOINT TEMPERATURES IN THE MID 70S...WILL CREATE HEAT INDEX VALUES IN THE 104-108 DEGREE RANGE DURING THE EARLY AND MID AFTERNOON HOURS THROUGHOUT SOUTHEAST GEORGIA AND NORTHEAST FLORIDA. THESE DANGEROUSLY HOT HEAT INDICES WILL PERSIST INTO THE LATE AFTERNOON HOURS FOR INTERIOR LOCATIONS. PERSONS WORKING OR PLANNING EXERCISE OUTDOORS THIS AFTERNOON SHOULD AVOID OVEREXERTION AND SHOULD STAY HYDRATED WITH PLENTY OF WATER AND TAKE AT LEAST HOURLY BREAKS IN THE SHADE OR AIR CONDITIONING. THE HEAT INDEX IS A MEASURE OF HOW HOT IT FEELS WHEN THE EFFECTS OF HUMIDITY ARE COMBINED WITH THE TEMPERATURE. A HEAT INDEX OF 105 DEGREES IS CONSIDERED THE LEVEL WHERE MANY PEOPLE BEGIN TO EXPERIENCE EXTREME DISCOMFORT OR PHYSICAL STRESS. THE HEAT INDEX IS MEASURED UNDER SHADY CONDITIONS...AND DIRECT EXPOSURE TO SUNLIGHT CAN INCREASE THE HEAT INDEX AS MUCH AS 15 DEGREES. PETS CAN ALSO SUCCUMB TO THE EFFECTS OF EXCESSIVE HEAT. INSURE PETS HAVE ADEQUATE DRINKING WATER AND A SHADY PLACE TO REST. DO NOT KEEP PETS IN CARS WITH WINDOWS ROLLED UP...EVEN PARTIALLY. TEMPERATURES INSIDE A CAR WITH THE WINDOWS UP CAN REACH OVER 150 DEGREES QUICKLY...RESULTING IN HEAT STROKE AND DEATH. NELSON
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE JACKSONVILLE FL
517 PM EDT MON AUG 12 2013
FLZ025-122200-
DUVAL-
517 PM EDT MON AUG 12 2013
...A SIGNIFICANT WEATHER ADVISORY HAS BEEN ISSUED FOR NORTHERN DUVAL
COUNTY FOR STRONG WINDS AND EXCESSIVE LIGHTNING VALID UNTIL 600 PM
EDT...
AT 517 PM EDT NATIONAL WEATHER SERVICE DOPPLER RADAR INDICATED A
STRONG THUNDERSTORM CENTERED 2 MILES SOUTH OF JACKSONVILLE
INTERNATIONAL AIRPORT...MOVING NORTHWEST AT 5 MPH. THIS STRONG
THUNDERSTORM WILL ALSO AFFECT AREAS AROUND JACKSONVILLE INTERNATIONAL
AIRPORT THROUGH 600 PM EDT. EXCESSIVE CLOUD-TO-GROUND LIGHTNING AND
GUSTY WINDS OF 45 TO 55 MPH CAN BE EXPECTED ALONG WITH POSSIBLE MINOR
DAMAGE.
REPORT DAMAGE TO THE NEAREST LAW ENFORCEMENT AGENCY OR YOUR COUNTY
EMERGENCY MANAGEMENT.
LAT...LON 3038 8173 3047 8183 3051 8179 3050 8179
3053 8176 3054 8174 3056 8173 3057 8170
3056 8169 3043 8165
TIME...MOT...LOC 2117Z 147DEG 3KT 3045 8172
PETERSONThe Jacksonville radar (KJAX), 76 km away, was scanning. The volume nearest the first event began at 21:22 UTC.
1 thunderstorm wind. Local standard time, as filed.
Two trees were blown down at the entrance to the Blythe Island Park. There was also damage to fencing. The time of the damage was based on radar.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Georgia in 2013Every state in 2013This day in weather historyWarnings in Georgia, August 2013
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: 470486.