Convection dropped from northwestern Ohio during the late afternoon and reached into southeast Ohio during the evening hours of the 4th.  This was south of an east to west cold front in northern Ohio. That front was sinking slowly south.   Surface dew points were in the mid 60s.
The convection consolidated into large cold clusters, first in eastern Ohio.  As these weakened, the clusters of showers and thunderstorms to their southwest got stronger.  These moved through southeast Ohio.  Rain amounts of 1.5 to 2 inches fell in less than 2 hours.  A few very localized amounts around 2.25 inches were likely.   The Jackson cooperative observer measured 2.03 inches.
One fatality occurred in Athens County.  Most of the flooding was confined to roads.  Damage occurred to vehicles that stalled when motorists drove through flooded roads.  Several motorists were rescued in Jackson and Gallia Counties.

Flash Flood in JACKSON, OHIO
From 04-MAY-12 21:45:00 to 05-MAY-12 04:30:00 (EST-5)
Location: GRAHAMSVILLE
Flood cause: Heavy Rain
Property damage: 250.00K
Crop damage: 0.00K
Reported by: Emergency Manager

Many roads were impassible.  Several water rescues occurred from stalled vehicles.  A woman was stranded in a park by high water and was rescued by boat.  Businesses in the community of Jackson saw urban runoff get inside.  This included the state motor vehicle registration building on Huron Street.  Condominiums were also flooded on Huron Street.

Flash Flood in VINTON, OHIO
From 04-MAY-12 21:45:00 to 05-MAY-12 02:30:00 (EST-5)
Location: JIMTOWN
Flood cause: Heavy Rain
Property damage: 150.00K
Crop damage: 0.00K
Reported by: Newspaper

Streams such as Pretty Run, Salt Creek, Middle Fork of Salt Creek, Raccoon Creek, and  Puncheon Fork,  flooded and damaged roads.  Culverts under some roads were damaged.  Private bridges were damaged.  Near MacArthur, some residents in a trailer park were evacuated. The American Red Cross gave assistance to 14 families in Vinton County.

Thunderstorm Wind in VINTON, OHIO
From 04-MAY-12 21:30:00 to 04-MAY-12 21:30:00 (EST-5)
Location: MC ARTHUR
Magnitude: 50.00 EG
Property damage: 5.00K
Crop damage: 0.00K
Reported by: Trained Spotter

Several trees were blown down.

Flash Flood in GALLIA, OHIO
From 04-MAY-12 23:30:00 to 05-MAY-12 04:30:00 (EST-5)
Location: SAND FORK
Flood cause: Heavy Rain
Property damage: 95.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Small streams flooded roads, such as State Route 141 and 325.  Several water rescues took place around Rio Grande.

Flash Flood in ATHENS, OHIO
From 04-MAY-12 20:51:00 to 05-MAY-12 02:30:00 (EST-5)
Location: NELSONVILLE
Flood cause: Heavy Rain
Property damage: 250.00K
Crop damage: 0.00K
Reported by: Law Enforcement

Small streams across the northern portion of the county flooded.
An elderly couple was driving home along Linscott Run.  This is a small tributary to Federal Creek near Amesville.  Close to home, the husband decided to stop his vehicle and wait out some high water.  Their vehicle became surrounded by rising water.  The couple made an attempt to walk to nearby higher ground.  The wife was using a walker due to recent hip surgery.  She slipped and the husband could not hold on to her.  The current swept her away.  The fire department located her body around dawn on the 5th, about a half mile downstream.  The husband was helped to safety by neighbors using a garden hose.   Route 550 was also flooded in Amesville.
Several streets in Nelsonville were flooded including along Dorr Run and Pleasant View Road.  Large dump rocks, used in the bypass construction, were even moved by the water.  A wall to a garage was knocked over by the water.  A house foundation was damaged.
A vehicle was flooded along Margaret Creek near Albany.  The occupants were unhurt at a nearby home when the local fire department arrived.

Lightning in ATHENS, OHIO
From 04-MAY-12 21:13:00 to 04-MAY-12 21:13:00 (EST-5)
Location: ATHENS
Property damage: 5.00K
Crop damage: 0.00K
Reported by: Law Enforcement

A feed store was struck.

Thunderstorm Wind in JACKSON, OHIO
From 04-MAY-12 21:32:00 to 04-MAY-12 21:32:00 (EST-5)
Location: CHAPMANS
Magnitude: 50.00 EG
Property damage: 5.00K
Crop damage: 0.00K
Reported by: Public

Several trees were blown down around the Fairgreens Country Club.