Thunderstorm Wind in Parke County, Indiana

A 60 mph thunderstorm wind gust was measured with a personal weather station.

The gradient between a ridge over the Appalachians and a trough just west of the region, quickly ejecting to the north-northeast...resulted in a robust low level jet (LLJ) of 45-60 mph at the 850 mb level. Strong wind shear between the LLJ and southerly surface flow of about 15 mph combined with modest yet adequate instability, to produce multiple lines of thunderstorms from the late afternoon into the evening. The strongest embedded cells brought the LLJ's winds, as well as isolated large hail to the surface over northwestern central Indiana. An initial line of thunderstorms produced the majority of the damage with a bookend vortex causing the most intense damage within Attica. A brief and stronger updraft caused 1 inch hail to fall in Montgomery county. Later, a convective line of showers with weak rotation caused additional tree damage in Clinton and Carroll counties.