Thunderstorm Wind in McLean County, Kentucky

A tree was blown down onto a structure in Livermore as a supercell storm moved through town.

Multiple rounds of severe thunderstorms impacted the Quad State region on the 27th. The later rounds of storms began with isolated to scattered storms tracking northeastward late afternoon into the early evening. On the synoptic scale, an upper level jet ejected across the Missouri Valley during the evening with a pronounced mid level wave moving through. The low level jet strengthened into the evening. A surface low was positioned near St Louis during the early evening with a trailing cold front extending southwestward. A broken band of supercells developed along this and eventually congealed into more linear segments as it moved into Southern Illinois and West Kentucky compared to its more discrete structure in Southeast Missouri.

In Northwest Kentucky, during the late evening, MLCAPE remained elevated ahead of the frontal boundary with values of 1000-2000J/kg, along with deep layer shear of 50-60kts, STP of 4-6, and mid-level lapse rates of 8C.

Reports from West Kentucky primarily came from an intensifying line of storms entering the Western Coal Fields area from the northwest. The most significant damage came from a surging portion of the line with an embedded supercell that resulted in two tornadoes: 1. an EF-0 tornado which crossed from northeastern Hopkins County into McLean County, and 2. an EF-1 tornado which caused damage from southeast of Rumsey to north of Livermore in McLean County. A swath of straight-line winds accompanied the first tornadic circulation. The tornadoes damaged numerous trees, some electrical lines and power poles, and a few homes and outbuildings. Several other straight-line wind damage reports were received.