Tornadoes · United States · Ohio · 2012

EF0 tornado, Lebanon Warren Co Ar to Genntown, Ohio, May 1, 2012

From Lebanon Warren Co Ar to Genntown, this EF0 tornado ran 0.0 miles across Warren County on May 1, 2012, touching down at 6:20 PM EDT and reaching 10 yards wide. It killed nobody, and did $5,000 of property damage.

The rating scale

Tracks are drawn in the color of the rating. The Enhanced Fujita scale rates the damage rather than measuring the wind: the speeds are what that damage is taken to imply.

  1. EF065 to 85 mphthis tornado

    Light damage. Surface peeled off some roofs, gutters and siding damaged, branches broken, shallow-rooted trees pushed over.

  2. EF186 to 110 mph

    Moderate damage. Roofs badly stripped, mobile homes overturned or badly damaged, exterior doors lost, windows broken.

  3. EF2111 to 135 mph

    Considerable damage. Roofs torn off well-built houses, frame homes shifted on their foundations, mobile homes destroyed, large trees snapped or uprooted, cars lifted off the ground.

  4. EF3136 to 165 mph

    Severe damage. Whole stories of well-built houses destroyed, large buildings badly damaged, trains overturned, trees debarked, heavy cars lifted and thrown.

  5. EF4166 to 200 mph

    Devastating damage. Well-built houses leveled, structures with weak foundations moved some distance, cars thrown and large missiles generated.

  6. EF5over 200 mph

    Incredible damage. Strong frame houses swept off their foundations, car-sized missiles thrown more than 100 meters, steel-reinforced concrete badly damaged, high-rise buildings deformed.

  7. Unrated

    The survey recorded a tornado but could not put a number on it, most often because it crossed open country and damaged nothing a rating can be read from.

The record

Rating
EF0
Date
May 1, 2012
Touchdown
6:20 PM EDT (22:20 UTC)
Lifted
6:21 PM EDT (22:21 UTC)
On the ground
1 minutes
Path length
0.0 miles (0.0 km)
Path width
10 yards (9 m)
Deaths
0
Injuries
0
Property damage
$5,000
County
Warren County
Touchdown point
39.440, -84.230
Lift-off point
39.440, -84.230
Record number
1205011620-01

What the Weather Service recorded

A warm front lifting across the Ohio Valley during the morning brought into the area a very unstable airmass. Numerous thunderstorms developed during the afternoon and evening. The environment was favorable for large hail and damaging winds. However, a few boundaries helped to produce localized favorable conditions for tornadoes. In addition, some storms occurred repeatedly over the same areas, causing an increased risk for flash flooding and flooding to occur.

The brief tornado touched down and caused damage to one structure, auto damage, and damage to outdoor furniture. Based on the damage surveyed, the maximum estimated wind speed of this tornado was 80 miles per hour.

The tornado touched down and uprooted or snapped about 10 to 15 trees. Minor structural damage also occurred. Based on the damage surveyed, the maximum estimated wind speed of this tornado was 80 miles per hour.

From NOAA NCEI's Storm Events Database, the narrative the local forecast office wrote for Storm Data.

The warnings

8 minutes of warning. NWS ILN issued a tornado warning for this county at 22:12 UTC, 8 minutes before the tornado touched down, in force until 22:45 UTC.

The county was under a tornado watch, issued at 19:05 UTC and running to 22:40 UTC.

Issued (UTC)ExpiredProductOffice
19:05 UTC22:40 UTCTornado WatchILN
21:52 UTC22:30 UTCSevere Thunderstorm WarningILN
22:12 UTC22:45 UTCTornado WarningILN
22:12 UTC02:15 UTCFlood AdvisoryILN
22:34 UTC23:00 UTCTornado WarningILN
22:40 UTC02:45 UTCTornado WatchILN
02:30 UTC05:30 UTCFlood AdvisoryILN
03:29 UTC03:48 UTCSevere Thunderstorm WarningILN
04:12 UTC08:15 UTCFlash Flood WarningILN

Every warning and watch covering the touchdown point that day, from the Iowa Environmental Mesonet's archive of National Weather Service products. Lead time is measured from the issue of the warning in force to the touchdown time in the database, both of which were recorded to the minute by different people.

The forecast that day

The Storm Prediction Center had this point in a Slight Risk, with a 0.05 chance of a tornado within 25 miles. The outlook in force was issued at 19:52 UTC.

SPC's Day 1 convective outlook as it stood when the tornado began, read at the touchdown point. The same archive is on the radar archive.

The air that afternoon

The radiosonde launches on either side of the tornado, from the nearest station that was launching then, drawn and analyzed the way Storm Lab does: the same diagram, the same parcel and shear definitions SPC's mesoanalysis uses.

Cncnati-Daytn, OH (KILN), 12:00Z

10.3 hours before the tornado, 37 km from the path. May 1, 2012.

Skew-T log-pSkew-T log-p diagram, Cncnati-Daytn, OH at 12:00Z on 2012-05-01Temperature and dew point through the depth of the atmosphere, with the mixed-layer parcel lifted from the surface. Mixed-layer CAPE 15 joules per kilogram, CIN -1, lifted condensation level 516 meters above ground. Wind barbs in knots down the right edge.LCLEL10008507005003002001001 km2 km3 km6 km9 km12 km15 km-30°-20°-10°10°20°30°40°
Temperature in red, dew point in green, the mixed-layer parcel dashed. The warm shading is its CAPE, the cool shading the inhibition it has to break through.
HodographHodograph, Cncnati-Daytn, OH at 12:00Z on 2012-05-01The wind through the lowest 10 kilometers as a curve, rings every 10 meters per second labeled in knots. Zero to 1 km storm-relative helicity 47 square meters per square second, 0 to 6 km bulk shear 36 knots.1939587897Sfc1 km3 km6 km9 kmRMLM
The wind turning with height, colored by layer: ground to 1 km, 1 to 3 km, 3 to 6 km, 6 to 10 km. RM and LM are the right and left moving storms Bunkers' method gives; the shaded area is the 0 to 1 km storm-relative helicity.
Mixed-layer CAPE
15 J/kg
Mixed-layer CIN
-1 J/kg
Surface CAPE
60 J/kg
Mixed-layer LCL
516 m above ground
0-6 km bulk shear
36 kt
0-1 km bulk shear
15 kt
0-1 km storm-relative helicity
47 m²/s²
0-3 km storm-relative helicity
93 m²/s²
Significant tornado parameter
0.0
Supercell composite
0.0
0-3 km lapse rate
4.9 K/km

Open this sounding in Storm Lab

The surface observations

Dayton (MGY), 17 km from the path, in the two hours either side.

Time (UTC)Temp (°F)Dew point (°F)WindGust (kt)Pressure (mb)Weather
20:53 UTC7364110° 6 kt1014.2
21:46 UTC71.664.480° 4 kt1013.9VCTS
21:53 UTC716480° 3 kt1014.2VCTS
22:10 UTC69.864.430° 5 kt1014.2VCTS +RA BR
22:24 UTC6866.2150° 12 kt1014.6+TSRA BR
22:31 UTC66.264.4170° 16 kt231014.9+TSRA BR
22:35 UTC66.262.6150° 9 kt231014.2-TSRA BR
22:53 UTC6762190° 11 kt1014.6VCTS
23:06 UTC66.262.6170° 7 kt1014.6VCTS
23:38 UTC66.262.6 3 kt1014.6-RA
23:49 UTC66.262.6250° 4 kt1014.9VCTS -RA BR
23:53 UTC6662250° 4 kt1014.9VCTS RA BR

From the Iowa Environmental Mesonet's archive of airport observations.

The radar

The Cincinnati radar (KILN), 35 km away, was scanning. The volume nearest the touchdown began at 22:20 UTC.

Open the radar archive at this moment, over the track

Reflectivity and velocity, decoded from the Level II archive in the browser. Volumes take a few seconds to open the first time.

What was reported nearby

Local storm reports within 60 km of the path, in the three hours either side.

Time (UTC)ReportWhereCountyRemark
21:27 UTCHAIL 1.75CincinnatiHamilton, OH
21:29 UTCHAIL 1.75White OakHamilton, OH
21:30 UTCHAIL 1White OakHamilton, OH
21:32 UTCHAIL 1DentHamilton, OH
21:33 UTCTSTM WND GST 55OxfordButler, OH
21:39 UTCHAIL 1WyomingHamilton, OH
21:55 UTCHAIL 1.75Deer ParkHamilton, OH
22:03 UTCFUNNEL CLOUDTrentonButler, OH
22:05 UTCFLOODWyomingHamilton, OH1 FOOT OF WATER FLOWING OVER ROAD
22:06 UTCHAIL 1New MarketHighland, OHHAIL DAMAGE TO CARS.
22:15 UTCTSTM WND GST 501 E MiddletownButler, OH
22:18 UTCHAIL 0.882 W WilmingtonClinton, OH
22:20 UTCHAIL 0.754 W WilmingtonClinton, OH
22:20 UTCTORNADO 01 Nw LebanonWarren, OHNWS STORM SURVEY CONFIRMS BRIEF EF0 TORNADO WITH MINOR DAMAGE TO A STRUCTURE AND AUTOMOBILE
22:24 UTCFLOODCincinnatiHamilton, OHHIGH WATER ACROSS THE COUNTY
22:24 UTCHAIL 11 W WilmingtonClinton, OH
22:24 UTCTORNADO 03 Nne LebanonWarren, OHNWS SURVEY CONFIRMS BRIEF EF0 TORNADO WITH MINOR TREE AND STRUCTURAL DAMAGE
22:25 UTCHAIL 1BataviaClermont, OH
22:30 UTCFUNNEL CLOUD2 N LebanonWarren, OH
22:33 UTCFUNNEL CLOUD1 E LebanonWarren, OH
23:00 UTCFLASH FLOOD3 S HarrisonHamilton, OHHIGH WATER FLOWING OVER LAWRENCEBURG ROAD IN MIAMI TOWNSHIP.
23:00 UTCFLASH FLOOD5 Ne ClevesHamilton, OHALMOST A FOOT OF FLOWING WATER OVER THE ROAD NEAR THE INTERSECTION OF HARRISON AVENUE AND WESSELMAN ROAD. ROAD ALSO CLOSED AT THE SAME TIME NEAR HARRISON AND RYBOLT ROAD TO TO HIGH WATER. BOTH INTERSECTIONS CLOSED BY COU
23:02 UTCTSTM WND DMG1 Nw LebanonWarren, OHHOME WITH MINOR DAMAGE
23:30 UTCFLASH FLOOD3 Ene HarrisonHamilton, OHABOUT 1 FOOT OF WATER FLOWING OVER MOUNT HOPE ROAD IN CROSBY TOWNSHIP. ROAD CLOSED BY COUNTY ENGINEERS OFFICE.
23:57 UTCTSTM WND DMG2 Sse Pleasant PlainClermont, OHTREE FELL ON ROOF OF HOUSE.
00:25 UTCFLOODSharonvilleHamilton, OHFLOODING OF ROADS AND PROPERTY AFTER 2.06 INCHES OF RAIN.

From the Iowa Environmental Mesonet's archive of National Weather Service local storm reports.

This ground now

The live radar over the trackEvery 2012 tornado in OhioEvery tornado in Ohio since 1950Warnings in force in Ohio nowThe forecast where you are

The other tornadoes of May 1, 2012

16 more were confirmed in the United States that day.

DateTimeRatingWherePath (mi)Width (yd)DeathsInjuriesDamage
May 11:30 AM CDTEF2Craig, OK1.01501$250,000
May 12:33 PM EDTEF0Clay, IN0.150$3,000
May 14:45 PM EDTEF0Trimble, KY1.915$25,000
May 13:59 PM CDTEF0Piatt, IL0.110
May 14:06 PM CDTEF1Champaign, IL8.175$25,000
May 15:28 PM EDTEF1Franklin, IN1.3100$250,000
May 14:40 PM CDTEF0Champaign, IL0.120
May 14:48 PM CDTEF0Pope, MN0.150
May 14:56 PM CDTEF0Stearns, MN0.975
May 15:05 PM CDTEF0Stearns, MN2.175$100,000
May 15:18 PM CDTEF0Vermilion, IL0.530$8,000
May 16:24 PM EDTEF0Warren, OH0.050$10,000
May 15:40 PM CDTEF0Wright, MN0.025
May 16:57 PM EDTEF0Fountain, IN0.150
May 17:36 PM EDTEF1Montgomery, IN0.5150$48,000
May 19:40 PM CDTEF0Clay, IA2.650$5,000

What this means

Ratings are the survey's, read off the damage rather than measured; the rating scale is above. Tornado counts rise through the record as reporting improved, so a year in the 1950s is not comparable with one today except for the strongest tornadoes, which were always noticed.

Sources

NOAA Storm Prediction Center tornado database, 1950-2025, the official record kept by NOAA's Storm Prediction Center.