Thunderstorm Wind in Randolph County, Indiana

Thunderstorm winds downed a two-foot diameter tree onto road, additional downed trees caused power outages.

At times robust south-southwesterly breezes brought unseasonably high dewpoints in the upper 60s and temperatures around 80 degrees, which led a favorable set-up for severe thunderstorms that also included high low-level helicity, and a 40-knot low-level jet stream ahead of an approaching cold front, all under adequate divergence aloft from the right exit region of a cyclonically curved jet streak.

Numerous rotating thunderstorms resulted through late day and evening hours, which produced widespread marginally severe hail across ten counties along and to the east-southeast of the Interstate 70 corridor, with strongest cells producing 1.50-1.75 inch hail and/or widely scattered wind damage from Clay County to Decatur County, as well as five weak tornadoes within Shelby, Rush and Decatur Counties. The tornadoes caused mainly tree damage and some minor structural damage. Several supercells actually tracked over the same areas where tornadoes occurred, which made video footage a key part of proper event verification. Some of the tornadoes may have actually had longer track lengths, but this could not be deciphered given the broad open farm fields. Witness reports indicated that some of the tornadoes were small, rope tornadoes that bounced across the landscape.

Less intense thunderstorms north of the Interstate 70 corridor produced small hail over a few zones, as well as a funnel cloud in Tipton County before an early evening cell downed a few trees in eastern Randolph County.