Slow moving thunderstorms in the vicinity of a cold front across southern Ohio produced heavy rainfall. As a result, some areas experienced flash flooding and flooding.
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 ILN wrote it up.
Slow moving thunderstorms in the vicinity of a cold front across southern Ohio produced heavy rainfall. As a result, some areas experienced flash flooding and flooding.
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 Wilmington, OH wrote its last area forecast discussion before the first event at May 21, 2:48 PM EST, 1 hour 27 minutes earlier.
AREA FORECAST DISCUSSION NATIONAL WEATHER SERVICE WILMINGTON OH 348 PM EDT MON MAY 21 2012 .SYNOPSIS... A WEAK COLD FRONT AND LOW PRESSURE SYSTEM WILL MOVE EAST ACROSS THE REGION TODAY. THE LOW WILL THEN REMAIN JUST SOUTHWEST OF THE REGION THROUGH WEDNESDAY. AN UPPER LEVEL RIDGE WILL THEN MOVE INTO THE AREA FOR THE END OF THE WEEK...BRINGING MUCH WARMER TEMPERATURES AND DRY CONDITIONS. && .NEAR TERM /UNTIL 6 AM TUESDAY MORNING/... ISOLATED SHOWERS AND WEAK THUNDERSTORMS HAVE DEVELOPED ACROSS THE CWA...MAINLY IN THE SOUTH AND SOUTHWEST PORTIONS. MORE CONCENTRATED THUNDERSTORM ACTIVITY IS OCCURRING SOUTH OF THE REGION (FLEMING COUNTY KY AND SOUTH). THE FRONT CROSSING THE REGION IS DIFFICULT TO PINPOINT. A WIND SHIFT HAS CLEARED THROUGH AT LEAST HALF OF THE CWA ALREADY...BUT THE DEWPOINT AXIS IS WELL BEHIND THE FRONT...STRETCHING SSW-TO-NNE THROUGH EASTERN INDIANA AND NORTHWEST OHIO AT 19Z. IT IS WITHIN THIS REGION...VERY SLOWLY SHIFTING EAST THROUGH THE NEXT FEW HOURS...THAT MOST OF THE SHOWER AND THUNDERSTORM DEVELOPMENT WILL BE FOCUSED. GIVEN THE LACK OF STRONG FORCING...COVERAGE IS NOT EXPECTED TO BE GREAT. STRONG STORMS ARE UNLIKELY GIVEN THE MINIMAL WIND SHEAR...BUT SLOW STORM MOTION MAY RESULT IN SOME HEAVY RAINFALL IN ONE OR TWO VERY LOCALIZED PLACES. EVEN AS THE CONVECTION WANES OVERNIGHT...THE MOISTURE AND CLOUD COVER WILL KEEP MIN TEMPERATURES FROM DROPPING VERY FAR. SO...EVEN BEHIND THE COLD FRONT...UPPER 50S TO LOWER 60S ARE EXPECTED (MAYBE SLIGHTLY LOWER IN THE FAR NORTHWEST). THUS...WILL RUN THE FORECAST A FEW DEGREES ABOVE GUIDANCE TEMPERATURES. && .SHORT TERM /6 AM TUESDAY MORNING THROUGH WEDNESDAY NIGHT/... A CLOSED UPPER LOW IS FORECAST TO DEVELOP IN THE CAROLINAS BY LATE TUESDAY...WITH WEAK SURFACE LOW PRESSURE EXTENDING NORTH INTO THE MIDDLE APPALACHIANS (SOMEWHAT A REMNANT OF THE FRONT AND LOW CROSSING THE AREA TODAY). SHOWERS AND POSSIBLY SOME WEAK THUNDERSTORMS WILL BE POSSIBLE IN THE REGIONS CLOSEST TO THIS FEATURE...MAINLY THE SOUTHEAST PART OF THE CWA...ON BOTH TUESDAY AND WEDNESDAY. THE WEATHER GRIDS ARE SKEWED HEAVILY TOWARD THE DIURNAL CYCLE...AS THE WEAK FORCING INDICATES THAT THIS WILL PRIMARILY BE AN INSTABILITY-DRIVEN SITUATION. AT THE SAME TIME...A NARROW RIDGE OF HIGH PRESSURE WILL BE MOVING INTO THE GREAT LAKES AND LOWER OHIO VALLEY REGIONS. THE PRESSURE PATTERN WILL BECOME RATHER DIFFUSE BY WEDNESDAY...WITH MEAN SOUTHERLY FLOW BEGINNING TO SET UP AS THE PRESSURE GRADIENT TO THE WEST BEGINS TO TIGHTEN ON WEDNESDAY NIGHT AND INTO THURSDAY. THE ECMWF IS A LITTLE BIT SLOWER IN MOVING THE UPPER LOW OUT OF THE SOUTH...BUT THE OVERALL PATTERN IS IN AGREEMENT BETWEEN MODELS...WITH A WARMING AND DRYING TREND DURING THE TUESDAY THROUGH THURSDAY PERIOD. && .LONG TERM /THURSDAY THROUGH MONDAY/... PESKY UPR LVL CLOSED LOW TO THE SOUTHEAST OF THE REGION IS EXPECTED TO OPEN UP AND EJECT TO THE NE AS AN UPR LVL HIGH BEGINS TO BUILD ACRS THE WRN FORECAST AREA ON THURSDAY. THERE COULD STILL BE A VERY SMALL CHANCE FOR A POP UP SHOWER OR STORM THURSDAY IN THE FAR SE...BUT HAVE DECIDED TO STILL KEEP THE FORECAST DRY. TEMPERATURES WILL CONTINUE TO WARM TO ABOVE NORMAL READINGS. FOR THURSDAY NIGHT INTO SUNDAY...UPR LVL RIDGE WILL CONTINUE TO BUILD INTO THE OHIO VALLEY. A COLD FRONT WILL TRY TO NUDGE SOUTHWARD CLOSE TO THE FAR NRN ZONES FRIDAY AFTERNOON AND EVENING. HAVE KEPT IT DRY BUT IF THE FRONT GETS TOO CLOSE...A SLIGHT CHANCE OF A SHOWER OR STORM MAY HAVE TO BE ADDED. FOR SATURDAY INTO SATURDAY NIGHT...HAVE TAKEN A BLEND OF THE 00Z ECMWF AND NCEP/HPC WHICH KEEPS THE FRONT JUST NEAR OUR FAR NRN/NERN BORDER. HAVE KEPT A SLIGHT CHANCE OF PCPN FOR THESE LOCATIONS DURING THE AFTN AND EVENING. ON SUNDAY...RIDGE IS EXPECTED TO HAVE ITS BEST INFLUENCE ON THE REGION...SO SKIES SHOULD BE MOSTLY SUNNY WITH WEAK FRONTAL BOUNDARY EITHER DISSIPATING OR PUSHING NE OF THE REGION. DRY WX IS EXPECTED. AS FOR TEMPERATURES...THEY WILL WARM SLIGHTLY EACH DAY WITH HOT WEATHER EXPECTED THIS WEEKEND WITH HIGHS LOWER 90S. ON MONDAY...MEMORIAL DAY...UPR LVL RIDGE WILL BEGIN TO WEAKEN AND MOVE OFF TO THE EAST. TEMPERATURES WILL STILL BE HOT...AROUND 90. A POP UP SHOWER OR THUNDERSTORM IS POSSIBLE DURING THE HEAT OF THE DAY AS CAP ALOFT WEAKENS. && .AVIATION /20Z MONDAY THROUGH SATURDAY/... ONGOING CONVECTION IS STARTING TO FIRE OVER MUCH OF THE REGION AND WILL SPREAD EASTWARD THIS EARLY EVENING TO AFFECT CENTRAL OHIO TAF SITES LATER TODAY. OUTSIDE OF THE SHOWERS WITH ISOLATED THUNDERSTORMS...VFR CONDITIONS SHOULD PREVAIL. OUTLOOK...NO SIGNIFICANT WEATHER IS EXPECTED. && .ILN WATCHES/WARNINGS/ADVISORIES... OH...NONE. KY...NONE. IN...NONE. && SYNOPSIS...HATZOS NEAR TERM...HATZOS SHORT TERM...HATZOS LONG TERM...HICKMAN AVIATION...FRANKS
HAZARDOUS WEATHER OUTLOOK NATIONAL WEATHER SERVICE WILMINGTON OH 500 AM EDT MON MAY 21 2012 INZ050-058-059-066-073>075-080-KYZ089>100-OHZ026-034-035-042>046- 051>056-060>065-070>074-077>082-088-220900- WAYNE-FAYETTE IN-UNION IN-FRANKLIN IN-RIPLEY-DEARBORN-OHIO- SWITZERLAND-CARROLL-GALLATIN-BOONE-KENTON-CAMPBELL-OWEN-GRANT- PENDLETON-BRACKEN-ROBERTSON-MASON-LEWIS-HARDIN-MERCER-AUGLAIZE-DARKE- SHELBY-LOGAN-UNION OH-DELAWARE-MIAMI-CHAMPAIGN-CLARK-MADISON- FRANKLIN OH-LICKING-PREBLE-MONTGOMERY-GREENE-FAYETTE OH-PICKAWAY- FAIRFIELD-BUTLER-WARREN-CLINTON-ROSS-HOCKING-HAMILTON-CLERMONT-BROWN- HIGHLAND-ADAMS-PIKE-SCIOTO- 500 AM EDT MON MAY 21 2012 THIS HAZARDOUS WEATHER OUTLOOK IS FOR EAST CENTRAL INDIANA...SOUTHEAST INDIANA...NORTHEAST KENTUCKY...NORTHERN KENTUCKY...CENTRAL OHIO...MIAMI VALLEY OF OHIO...SOUTH CENTRAL OHIO...SOUTHWEST OHIO AND WEST CENTRAL OHIO. .DAY ONE...TODAY AND TONIGHT. NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME. .DAYS TWO THROUGH SEVEN...TUESDAY THROUGH SUNDAY. NO HAZARDOUS WEATHER IS EXPECTED AT THIS TIME. .SPOTTER INFORMATION STATEMENT... SPOTTER ACTIVATION IS NOT EXPECTED AT THIS TIME.
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE WILMINGTON OH
347 PM EDT MON MAY 21 2012
OHZ078-212015-
CLERMONT OH-
347 PM EDT MON MAY 21 2012
...A STRONG THUNDERSTORM WILL AFFECT WESTERN CLERMONT COUNTY THROUGH
415 PM EDT...
AT 348 PM EDT...RADAR INDICATED A STRONG THUNDERSTORM NEAR
SUMMERSIDE...MOVING SOUTH AT 5 MPH.
WIND GUSTS TO 30 MPH AND ONE HALF INCH DIAMETER HAIL ARE POSSIBLE
WITH THIS STORM.
SOME LOCATIONS THAT MAY BE AFFECTED INCLUDE...WITHAMSVILLE...BATAVIA
AND AMELIA.
ALSO...MOUNT CARMEL AND WILLOWVILLE ARE NEAR THE PATH OF THIS STRONG
THUNDERSTORM.
LAT...LON 3902 8432 3907 8432 3907 8431 3917 8430
3919 8428 3919 8424 3903 8410 3902 8431SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE WILMINGTON OH 401 PM EDT MON MAY 21 2012 KYZ099-100-OHZ079-081-212015- LEWIS KY-MASON KY-ADAMS OH-BROWN OH- 401 PM EDT MON MAY 21 2012 ...A STRONG THUNDERSTORM WILL AFFECT SOUTHEASTERN BROWN... SOUTHWESTERN ADAMS...EASTERN MASON AND NORTHWESTERN LEWIS COUNTIES THROUGH 415 PM EDT... AT 400 PM EDT...RADAR INDICATED A STRONG THUNDERSTORM NEAR BRADYSVILLE...MOVING SOUTHEAST AT 5 MPH. WIND GUSTS TO 30 MPH AND ONE HALF INCH DIAMETER HAIL ARE POSSIBLE WITH THIS STORM. SOME LOCATIONS THAT MAY BE AFFECTED INCLUDE...MANCHESTER. ALSO...BENTONVILLE...BRADYSVILLE...SOMO AND TRINITY ARE NEAR THE PATH OF THIS STRONG THUNDERSTORM. LAT...LON 3867 8350 3856 8374 3875 8379 3880 8368
SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE WILMINGTON OH
425 PM EDT MON MAY 21 2012
KYZ093-OHZ077-078-212045-
CAMPBELL KY-HAMILTON OH-CLERMONT OH-
425 PM EDT MON MAY 21 2012
...A STRONG THUNDERSTORM WILL AFFECT WESTERN CLERMONT...SOUTHEASTERN
HAMILTON AND CAMPBELL COUNTIES THROUGH 445 PM EDT...
AT 422 PM EDT...RADAR INDICATED A STRONG THUNDERSTORM NEAR CHERRY
GROVE...MOVING SOUTH AT 15 MPH.
WIND GUSTS TO 30 MPH AND ONE HALF INCH DIAMETER HAIL ARE POSSIBLE
WITH THIS STORM.
SOME LOCATIONS THAT MAY BE AFFECTED INCLUDE...
WITHAMSVILLE...MELBOURNE...AMELIA...NEW PALESTINE...
LINDALE...BLAIRSVILLE...AND NEW RICHMOND.
LAT...LON 3897 8418 3893 8427 3896 8437 3913 8442
3914 8430
HATZOSSPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE WILMINGTON OH
425 PM EDT MON MAY 21 2012
OHZ080-212045-
HIGHLAND OH-
425 PM EDT MON MAY 21 2012
...A STRONG THUNDERSTORM WILL AFFECT CENTRAL HIGHLAND COUNTY THROUGH
445 PM EDT...
AT 424 PM EDT...RADAR INDICATED A STRONG THUNDERSTORM NEAR RUSSELL...
MOVING NORTH AT 5 MPH.
WIND GUSTS TO 30 MPH AND ONE HALF INCH DIAMETER HAIL ARE POSSIBLE
WITH THIS STORM.
SOME LOCATIONS THAT MAY BE AFFECTED INCLUDE...HILLSBORO AND
LYNCHBURG.
ALSO...RUSSELL IS NEAR THE PATH OF THIS STRONG THUNDERSTORM.
LAT...LON 3922 8382 3923 8380 3926 8379 3928 8375
3931 8361 3910 8351 3905 8377SPECIAL WEATHER STATEMENT
NATIONAL WEATHER SERVICE WILMINGTON OH
434 PM EDT MON MAY 21 2012
KYZ100-OHZ081-212100-
LEWIS KY-ADAMS OH-
434 PM EDT MON MAY 21 2012
...A STRONG THUNDERSTORM WILL AFFECT SOUTHERN ADAMS AND NORTHERN
LEWIS COUNTIES THROUGH 500 PM EDT...
AT 430 PM EDT...RADAR INDICATED A STRONG THUNDERSTORM NEAR STATE
ROUTE 348 AT STATE ROUTE 125...MOVING SOUTHEAST AT 5 MPH.
WIND GUSTS TO 30 MPH AND ONE HALF INCH DIAMETER HAIL ARE POSSIBLE
WITH THIS STORM.
THE STRONG THUNDERSTORM WILL AFFECT MAINLY RURAL AREAS OF NORTHERN
LEWIS AND SOUTHERN ADAMS COUNTIES...INCLUDING BLUE CREEK...CARRS...
CONCORD AND ROME.
LAT...LON 3878 8361 3889 8343 3874 8327 3872 8327
3860 8347SPECIAL WEATHER STATEMENT NATIONAL WEATHER SERVICE WILMINGTON OH 446 PM EDT MON MAY 21 2012 OHZ079-081-212115- ADAMS OH-BROWN OH- 446 PM EDT MON MAY 21 2012 ...A STRONG THUNDERSTORM WILL AFFECT SOUTHEASTERN BROWN AND SOUTHWESTERN ADAMS COUNTIES THROUGH 515 PM EDT... AT 443 PM EDT...RADAR INDICATED A STRONG THUNDERSTORM NEAR REDOAK... MOVING SOUTHEAST AT 5 MPH. WIND GUSTS TO 30 MPH AND PENNY SIZE HAIL ARE POSSIBLE WITH THIS STORM. THE STRONG THUNDERSTORM WILL AFFECT MAINLY RURAL AREAS OF SOUTHEASTERN BROWN AND SOUTHWESTERN ADAMS COUNTIES...INCLUDING BRADYSVILLE AND BENTONVILLE. LAT...LON 3876 8352 3865 8371 3877 8387 3887 8373
The Cincinnati radar (KILN), 27 km away, was scanning. The volume nearest the first event began at 21:13 UTC.
4 flash flood, 1 heavy rain, 1 flood. Local standard time, as filed.
Several inches of water were reported on Route 50 near Mad River Road due to heavy rainfall.
Motorists were stranded on Highway 52 due to high water caused by heavy rainfall.
High water was reported over Highway 52 near old State Route 68. Fire crews were working to clean up roadways.
Three to four feet of water was reported over Highway 52 between Higginsport and Ripley. Mud was covering the roadway near Free Soil Road. A tree was downed across A and P Road. Fire crews were working to clean up the roadways. This flooding occurred due to persistent heavy rainfall.
There were numerous reports of rapidly rising water across the central and western parts of the county due to heavy rainfall. More specifically, Highway 50 near Mad River Road, North High Street near Hobart Drive, and Carey Road near Fallsville Wilderness Area were all closed. A ballpark in Hillsboro was submerged.
A couple of roads were closed in the area due to high water caused by heavy rainfall.
After NWS Directive 10-1605, the rules offices file Storm Data by.
Every storm in Ohio in 2012Every state in 2012This day in weather historyWarnings in Ohio, May 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: 382643, 382639, 382640, 382644, 382642, 382646.