An isolated severe thunderstorm developed along a boundary collision in central Volusia County and produced wind damage.
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 MLB wrote it up.
An isolated severe thunderstorm developed along a boundary collision in central Volusia County and produced wind damage.
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 Melbourne, FL wrote its last area forecast discussion before the first event at Aug 13, 1:42 PM EST, 3 hours 13 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE MELBOURNE FL 242 PM EDT SAT AUG 13 2011 .DISCUSSION... TONIGHT...WEAK PRESSURE GRADIENT EXTENDS FROM HIGH PRESSURE OFF NY...NJ...VA TO THE BAHAMA ISLANDS AND CUBA. A MOISTURE RIBBON STRETCHES FROM THE SOUTHEAST GULF OF MEXICO ACROSS THE FLORIDA STRAIT AND SOUTH FLORIDA AND WELL AHEAD OF SURFACE TROUGHING OVER THE SOUTHEAST. WINDS SHOULD SHIFT BACK TO THE SOUTH AND SOUTHWEST ONCE THE EAST COAST SEA BREEZE INFLUENCE DIMINISHES LATE IN THE EVENING. SKIES WILL BE PARTLY TO MOSTLY CLOUDY FROM THE AFTERNOON AND EARLY EVENING CONVECTION THEN PARTLY CLOUDY AFTER MIDNIGHT. CLOUD COVER WILL INHIBIT ANY RADIATIONAL COOLING UNTIL AFTER MIDNIGHT THUS ANOTHER WARM NIGHT WITH LOWS IN THE MID AND UPPER 70S. SUN-MON NIGHT...GFS DEPICTS BROAD TROUGH ALOFT OVER THE EASTERN HALF OF THE UNITED STATES DROPPING SOUTH AND SOUTHEAST AND PUSHING DOWN THE FLORIDA PENINSULA OVERNIGHT MONDAY. USUALLY THAT IS NOT THE CASE FOR THE SUMMER MONTHS BUT LOOKING BACK WEST OVER THE EASTERN PACIFIC AND THE GULF OF ALASKA...IT MAY HAVE SOME BACKING AS THE FLOW AROUND THE DEEP TROUGH ALOFT EXTENDING FROM THE GULF OF ALASKA INTO THE EASTERN PACIFIC AND THE RIDGE OVER THE ROCKIES COULD DRIVE THE TROUGH SOUTH ENOUGH INTO NORTHERN FLORIDA OR FURTHER. THE PERSISTENT TROUGH OVER THE SOUTHEAST WILL KEEP THE RIDGE OF HIGH PRESSURE SUPPRESSED TO THE SOUTH AND RESULT IN A CONTINUED SOUTHWEST TO WEST FLOW ACROSS EAST CENTRAL FLORIDA. IF THERE IS ENOUGH SUN EACH DAY AFTERNOON SEA BREEZES SHOULD FORM AND PUSH SLOWLY DURING THE MID AND LATE AFTERNOON. HIGHS IN THE MIDDLE 90S INTERIOR AND THE LOW 90S AT THE COAST. OVERNIGHT LOWS IN THE MIDDLE 70S INTERIOR AND THE MIDDLE AND THE UPPER 70S AT THE COAST. PREVIOUS EXTENDED... TUE-FRI...THE AREA IS FORECAST TO BE UNDER UPPER TROUGHING INTO AT LEAST TUE BEFORE STRENGTHENING/EASTWARD EXPANDING RIDGE ACROSS THE CENTRAL/WESTERN CONUS PUSHES THE WEAKENING TROUGH FURTHER INTO THE WESTERN ATLANTIC. MODEL GUIDANCE HAS COME IN WITH AMPLE PRECIPITABLE WATER VALUES FOR THIS PERIOD. THE FAIRLY WEAK SURFACE PRESSURE GRADIENT WILL ALLOW FOR LIGHT OFFSHORE WINDS TO CONTINUE THROUGH TUE BEFORE AN ONSHORE FLOW DEVELOPS FOR WED-FRI. THE EAST COAST SEA BREEZE SHOULD HAVE BETTER INLAND PENETRATION WED-FRI. STEERING FLOW FOR STORMS REMAINS WESTERLY OR SOUTHWESTERLY THROUGH WED...BUT DOES WEAKEN THROUGH THIS TIME. FOR THU-FRI THE STEERING FLOW BECOMES RELATIVELY WEAK/ERRATIC AND PERHAPS A BIT MORE SOUTHERLY. HOWEVER...THE NECESSARY INGREDIENTS REMAIN IN PLACE TO CONTINUE 40 PERCENT POPS THROUGH THIS PERIOD. SLIGHTLY ABOVE NORMAL MAX TEMPS SHOULD PERSIST INTO MID-WEEK...MID 90S INTERIOR AND LOW 90S COAST. WITH THE ONSHORE FLOW DEVELOPING OVER THE LATTER PORTION OF THIS PERIOD MAX TEMPERATURES MAY BE A COUPLE DEGREES LOWER. MIN TEMPERATURES CONTINUE IN THE 70S. && .AVIATION... RADAR LOOPS SHOW SHOWERS AND STORMS MOVING SOUTHWEST TO NORTHEAST ACROSS EAST CENTRAL FLORIDA. LATEST ROUND OF METARS SHOW THAT A SEA BREEZE HAS FORMED AT THE COAST AND WILL MOVE SLOWLY INLAND AGAINST THE PREVAILING SOUTHWEST TO WEST FLOW. BOUNDARY COLLISION MOST LIKELY TO OCCUR LATE AFTERNOON LAKE GEORGE TO MCO...ISM AND SOUTH. TEMPO MVFR CONDITIONS IN AND NEAR STORMS THROUGH 02Z. VFR AFTER 02Z. && .MARINE... SUN-MON... BROAD TROUGHING OVER THE SOUTHEAST WILL RESULT IN A PREVAILING SOUTHWEST TO WEST WIND PATTERN OVERNIGHT AND SUN MORNING. SEA BREEZE SHOULD FORM EARLY AFTERNOON AT THE IMMEDIATE COAST AND SLOWLY PUSH INLAND AGAINST THE PREVAILING SOUTHWEST TO WEST WIND FLOW. SAME PATTERN FOR MON. TUE-THU...TROUGH REMAINS OVER THE SOUTHEAST AND FLORIDA. SOUTHWEST TO WEST WINDS EXCEPT FOR AFTERNOON SEA BREEZES AT THE COAST. && .PRELIMINARY POINT TEMPS/POPS... DAB 76 94 76 93 / 20 40 20 40 MCO 76 95 76 94 / 20 40 20 40 MLB 76 91 75 92 / 20 40 20 40 VRB 76 92 75 92 / 20 40 20 40 LEE 78 95 78 95 / 20 40 20 40 SFB 78 96 78 96 / 20 40 20 40 ORL 78 96 78 95 / 20 40 20 40 FPR 74 91 75 92 / 20 40 20 40 && .MLB WATCHES/WARNINGS/ADVISORIES... FL...NONE. AM...NONE. && SHORT TERM/AVIATION...WIMMER IMPACT WEATHER UPDATES...PENDERGRAST
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE MELBOURNE FL 1155 AM EDT SAT AUG 13 2011 AMZ550-552-555-570-572-575-FLZ041-044>047-053-054-058-059-064-141- 144-147-132100- COASTAL WATERS FROM FLAGLER BEACH TO VOLUSIA BREVARD COUNTY LINE OUT 20 NM- COASTAL WATERS FROM VOLUSIA BREVARD COUNTY LINE TO SEBASTIAN INLET OUT 20 NM- COASTAL WATERS FROM SEBASTIAN INLET TO JUPITER INLET OUT 20 NM- WATERS FROM FLAGLER BEACH TO VOLUSIA BREVARD COUNTY LINE 20 TO 60 NM OFFSHORE- WATERS FROM VOLUSIA BREVARD COUNTY LINE TO SEBASTIAN INLET 20 TO 60 NM OFFSHORE- WATERS FROM SEBASTIAN INLET TO JUPITER INLET 20 TO 60 NM OFFSHORE- INLAND VOLUSIA-NORTHERN LAKE-ORANGE-SEMINOLE-SOUTHERN BREVARD- OSCEOLA-INDIAN RIVER-OKEECHOBEE-ST. LUCIE-MARTIN-COASTAL VOLUSIA- SOUTHERN LAKE-NORTHERN BREVARD- 1155 AM EDT SAT AUG 13 2011 THIS HAZARDOUS WEATHER OUTLOOK IS FOR EAST CENTRAL FLORIDA. .DAY ONE...TODAY AND TONIGHT. .THUNDERSTORM IMPACT... THE EAST COAST SEA BREEZE BOUNDARY WILL PUSH SLOWLY INLAND THIS AFTERNOON. ISOLATED TO SCATTERED STORMS WILL FORM ALONG OR JUST INLAND FROM THE COAST OF MARTIN...SAINT LUCIE AND INDIAN RIVER COUNTIES. INCREASING MOISTURE AND INSTABILITY ALOFT SHOULD PRODUCE A HIGHER COVERAGE OF STORMS OVER THE INTERIOR COUNTIES DURING THE AFTERNOON INTO EARLY THIS EVENING...WHICH INCLUDES LAKE COUNTY AND ADJACENT PORTIONS OF INTERIOR VOLUSIA...SEMINOLE...WESTERN ORANGE AND NORTHWEST OSCEOLA COUNTIES. THE PRIMARY THREATS WILL BE FREQUENT TO EXCESSIVE LIGHTNING STRIKES...STRONG DOWNBURST WINDS UP TO 50 MPH AND VERY HEAVY RAIN. AN ISOLATED SEVERE STORM WITH DAMAGING WINDS CANNOT BE RULED OUT. STORM MOTION WILL BE SLOW AND ERRATIC. .FLOOD IMPACT... SLOW STORM MOTION WILL CONTRIBUTE TO THE POTENTIAL FOR LOCALLY HEAVY RAIN WHICH MAY ACCUMULATE GREATER THAN 2 INCHES IN A SHORT PERIOD OF TIME CAUSING TEMPORARY FLOODING OF SOME LOW LYING AND POOR DRAINAGE AREAS ESPECIALLY IN URBAN AREAS. .EXCESSIVE HEAT IMPACT... TEMPERATURES IN THE LOW TO MID 90S WILL COMBINE WITH HUMIDITY TO PRODUCE HEAT INDICES AROUND 105 FOR AT LEAST A COUPLE OF HOURS. IF YOU WILL BE SPENDING A PROLONGED PERIOD OUTDOORS...DRINK PLENTY OF WATER AND TAKE FREQUENT BREAKS OUT OF THE SUN. .RIP CURRENT IMPACT... WEATHER AND OCEAN CONDITIONS WILL PRODUCE AN ELEVATED THREAT FOR RIP CURRENTS AT THE BEACHES OF EAST CENTRAL FLORIDA. ALWAYS SWIM WITHIN SIGHT OF A LIFEGUARD. .MARINE THUNDERSTORM GUST IMPACT... STORMS WILL MAINLY IMPACT INLAND LAKES AND WATERWAYS INTO EARLY EVENING...ALTHOUGH ONE OR TWO STORMS MAY AFFECT THE INTRACOASTAL WATERS SOUTH OF SEBASTIAN INLET. A FEW STRONG STORMS WILL BE CAPABLE OF PRODUCING WIND GUSTS OF 35 TO 45 KNOTS AND FREQUENT LIGHTNING STRIKES. STORM MOTION WILL BE SLOW AND ERRATIC. .WATERSPOUT IMPACT... MOISTURE AND LIGHT WINDS THROUGH A DEEP LAYER OF THE ATMOSPHERE WILL SUPPORT THE FORMATION OF WATERSPOUTS. THE PRIMARY AREA OF CONCERN WILL BE DURING DEVELOPMENT OF THE EAST COAST SEA BREEZE. ANOTHER FAVORED AREA FOR WATERSPOUTS IS BETWEEN MOSQUITO LAGOON AND COCOA BEACH. THE FOCUS FOR SPOUT FORMATION WILL SHIFT TO THE INTERIOR DURING THE AFTERNOON AND EARLY EVENING AS OUTFLOW AND SEA BREEZE BOUNDARIES COLLIDE. BOATERS SHOULD AVOID WATERSPOUTS AS THEY CAN TIP OR SWAMP SMALL CRAFT. IF A WATERSPOUT APPROACHES YOU ON LAND...SEEK SHELTER IN AN ENCLOSED STURDY BUILDING. .DAYS TWO THROUGH SEVEN...SUNDAY THROUGH FRIDAY. SCATTERED LIGHTNING STORMS ARE EXPECTED EACH AFTERNOON WITH A GOOD CHANCE FOR STORMS PUSHING OFFSHORE SUNDAY AND MONDAY. .SPOTTER INFORMATION STATEMENT... SPOTTERS ARE REQUESTED TO MONITOR THE WEATHER AND SELF ACTIVATE IF NEEDED. KELLY/PENDERGRAST
SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE MELBOURNE FL 444 PM EDT SAT AUG 13 2011 FLZ041-044>047-053-141-144-147-132245- COASTAL VOLUSIA-INLAND VOLUSIA-NORTHERN BREVARD-NORTHERN LAKE-ORANGE- OSCEOLA-SEMINOLE-SOUTHERN BREVARD-SOUTHERN LAKE- 444 PM EDT SAT AUG 13 2011 ...A SIGNIFICANT WEATHER ADVISORY HAS BEEN ISSUED FOR... THE OSCEOLA BREVARD COUNTY LINE NORTH TO LAKE AND INTERIOR VOLUSIA COUNTIES... STRONG THUNDERSTORMS HAVE BEGUN TO FORM ALONG MULTIPLE BOUNDARY COLLISIONS ACROSS EAST CENTRAL FLORIDA. THESE STORMS ARE ONGOING AND WILL CONTINUE TO INCREASE IN COVERAGE THROUGH THIS EVENING...FROM OSCEOLA COUNTY NORTH TO LAKE AND INTERIOR VOLUSIA COUNTIES...AS ADDITIONAL BOUNDARIES AND STORMS DEVELOP. WIND GUSTS OF 45 TO 50 MPH...FREQUENT CLOUD TO GROUND LIGHTNING AND LOCALLY HEAVY RAINFALL WILL BE THE PRIMARY THREATS FROM THIS ACTIVITY AS STORMS WILL PROPAGATE AND DRIFT SLOWLY ALONG BOUNDARIES. SMALL HAIL WILL ALSO BE POSSIBLE ALTHOUGH NOT AS LIKELY. TAKE SHELTER INSIDE IF CAUGHT NEAR ONE OF THESE STORMS AND BE CAUTIOUS IF OUT ON AREA ROADWAYS. GUSEMAN
The Melbourne radar (KMLB), 125 km away, was scanning. The volume nearest the first event began at 21:56 UTC.
1 thunderstorm wind. Local standard time, as filed.
A trained spotter reported that a large tree was blown over onto a mobile home and a car during a thunderstorm just north of Deland. Multiple power lines were also blown down in the vicinity.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Florida in 2011Every state in 2011This day in weather historyWarnings in Florida, August 2011
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: 321930.