Thunderstorm Wind in Bullitt County, Kentucky

Power and phone lines were blown down by strong thunderstorm winds between Stringer Lane and Greenwell Ford Road.

An upper level low which had meandered over the mid-Mississippi Valley for several days began to eject northeastward, opening up into a trough on June 18th. At the surface, low pressure developed over Missouri and Illinois as a cold front sagged slowly to the south and east. During the late morning and early afternoon hours, showers and thunderstorms developed along a remnant outflow boundary and pushed eastward across Illinois. Ahead of the storms, a strongly unstable environment was present across southern Indiana and central Kentucky, as temperatures warmed into the mid-to-upper 80s and dew point temperatures were in the low-to-mid 70s. This resulted in around 3000 J/kg MLCAPE and 4000 J/kg SBCAPE over the area during the afternoon hours, providing plenty of energy for storms to work with. The strongest mid-level flow and deep-layer shear during this event was located over central Indiana; however, there was still 25-35 knots of effective bulk shear which helped to keep storms organized into multicell clusters which eventually grew upscale into a broken line. While reasonably steep mid-level lapse rates and the initially discrete nature of convection allowed for a few instances of severe hail in southern Indiana, the main severe hazard with this event were damaging straight-line winds, with scattered wind damage and measured severe wind gusts observed across southern Indiana and central Kentucky. A second wave of strong to occasionally severe thunderstorms moved through during the late evening hours, though increased stability limited wind damage to much more isolated instances.