Thunderstorm Wind in Massac County, Illinois

The garage door of a metal outbuilding was blown in.

In the base of an approaching upper-level trough, strong mid and upper-level jets overspread the middle Mississippi Valley on the afternoon of the 30th. Steep mid-level lapse rates contributed to rapid destabilization, as well, setting the stage for a widespread severe thunderstorm event. As the cold front approached, thunderstorms rapidly intensified and quickly formed into line segments upon reaching southern Illinois in the mid-afternoon. Large hail was common through the late afternoon in areas west of Interstate 57 and north of Highway 13. Quarter size to golf ball size hail was reported over much of this area. Then the storms formed into a larger line and produced damaging winds. During this transition, one storm produced an EF-1 tornado that moved east across central portions of Alexander and Pulaski Counties. Widespread 70-90mph winds swept along just south of the tornado and eventually overtook it.