Thunderstorm Wind in Tippecanoe County, Indiana

Observed thunderstorm wind gust to 75 mph at KLAF Purdue University Airport coincided with tree damage from thunderstorm winds in West Lafayette, just before thunderstorm winds snapped a couple trees on Purdue University campus.

Hot and very humid conditions with afternoon temperatures in the low 90s and dewpoints as high as 79 degrees at Shelbyville and 77 degrees at Bloomington promoted abundant instability of 3000-4000 J/kg of CAPE, which coupled with adequate wind shear to produce a few late day rotating supercells. A few reports of 1.00 inch hail were received from Rush, Brown and Decatur Counties, while sub-severe hail fell over northern Johnson County.

More organized and widespread severe weather then approached central Indiana from the west-northwest during the late evening. This slowly-weakening derecho, which had produced dozens of tornadoes and numerous gusts over 75 mph from eastern Iowa to areas south of Chicago...slowly weakened in a bowing pattern, producing a measured 75 mph gust at Lafayette. A mixture of tree/power line damage and sub-severe winds then crossed northern portions of central Indiana, with greatest damage in Howard and Hamilton Counties. Severe winds continued into the first 15 minutes of the 16th (LST) across Marion County, before weakening while continuing to the east-southeast.