Thunderstorm Wind in Carlisle County, Kentucky

Widespread wind damage occurred around the county. Numerous trees were blown down, including some trees on power lines. A tree fell on a house in Milburn and also in the Cunningham area on County Road 1054. U.S. Highway 62 between Cunningham and Bardwell was impassable due to downed trees on the road. A 67-year-old man was killed when he lost control of his motorcycle due to a fallen tree on Highway 121 near County Road 1031 (indirect fatality).

A severe thunderstorm complex raced southward across western Kentucky during the early evening hours. Widespread wind damage occurred with this long-lived complex, which met the definition of a derecho. This convective system took shape over the Missouri/Iowa border region and then progressed south-southeast to the Tennessee Valley by late evening. A very moist and unstable air mass set the stage for this derecho. Surface dew points were near 80 degrees, with mixed-layer capes over 4000 j/kg. When the atmosphere is that unstable, wind shear does not need to be particularly strong for significant severe weather to occur. The bulk wind shear in the 0 to 6 km layer averaged 20 to 30 knots. Deep northerly wind flow averaged around 20 knots from 850 to 500 mb on the front side of a high pressure ridge.