National Weather Service United States Department of Commerce
June 12-13, 2013
Multiple Rounds of Severe Weather

Three rounds of severe thunderstorms impacted the area from June 12-13, 2013, as a vigorous low pressure system moved through the Great Lakes and Ohio Valley. Most of the severe weather reports were caused by thunderstorm wind damage. However, there were also a few tornadoes and minor flooding of small streams due to repeated heavy rain in some areas.
Supercell thunderstorms developed over northern portions of central Ohio during the evening of Wednesday June 12. Generally sub-severe storms were found in the Wilmington, OH, forecast area, although one tornado warning was elicited as a rotating thunderstorm moved along the Delaware-Morrow county line. There were several reports of a rotating wall cloud with this storm, but no tornado touchdowns within Delaware County.
Clusters of thunderstorms over northern Illinois and Indiana congealed into a bowing mesoscale convective system during the late evening hours. This intense line of thunderstorms moved into west-central Ohio around 11:30PM. Numerous reports of wind damage occurred, mainly along and north of Interstate 70. The line weakened somewhat as it moved south and east, with the last reports of severe weather occurring around 2:30AM, although thunderstorms lingered well after that. A few brief, embedded tornadoes developed within the line.
Along the outflow boundary from the overnight storms, additional storms developed and strengthened on Thursday morning across southern Ohio in an airmass that remained unstable. These storms formed a line which moved to the southeast and produced scattered wind damage through the mid morning hours.