EF1 tornado in Union County, Illinois

Several dozen trees were uprooted or snapped. A vehicle was destroyed by a falling tree. At least a couple of buildings and houses sustained mostly minor roof damage, including the loss of some shingles. Peak winds were estimated near 90 mph. The average path width was 100 yards.

Numerous strong to severe thunderstorms occurred in the warm sector of a low pressure system over central Missouri. The air mass in the warm sector was very unstable, with afternoon mixed-layer cape values in the 2500 to 4000 j/kg range. A 65 to 75 knot mid level jet was located across Arkansas, with the nose of the jet moving into western Kentucky. This feature enhanced the lift and strong deep-layer shear already in place, creating an environment very favorable for supercells and tornadoes. A 40 to 55 knot low level jet across eastern Arkansas moved into western Kentucky during the evening, resulting in isolated tornadoes and widespread damaging winds.