Thunderstorm Wind in Nelson County, Kentucky

The National Weather Service conducted a storm survey on Thursday, March 19th for the storms that occurred early Monday morning, March 16th. Straight line winds were determined to have occurred in Nelson County near the Bardstown area with max winds

of 80 MPH.

Damage to trees occurred along the Bluegrass Parkway southwest of Bardstown, including trees damaged in an isolated nature within Bardstown city limits. South of Bardstown there was damage to trees and some structure, including a building at the Nelson County Fairgrounds and a barn with extensive roof loss along Highway 31E.

All damage was facing to the northeast, which is consistent with the storm motion and indicative of straight line winds. No rotational signatures were observed by the survey team.

During the late evening and overnight hours March 15th into March 16th, a strong upper level trough and associated cold front moved across the Ohio Valley. Ahead of the cold front, temperatures were in the 70s with dew point temperatures in the upper 50s and low 60s. This corridor of modest low-level destabilization contained between 250 and 500 J/kg of MLCAPE which was oriented immediately ahead of the surface front and the main line of showers and thunderstorms. With a corridor of 80 knot mid-level winds approaching from the west, effective bulk shear was between 40 and 50 knots for this event, creating a typical high-shear, low-CAPE setup for central Kentucky and southern Indiana. While the primary forcing mechanism was lifting along the cold front, resulting in a quasi-linear convective system, some scattered cells developed ahead of the main line of storms across western Kentucky. These storms had transient supercellular characteristics, and would go on to produce a swath of stronger winds and a few embedded tornadoes across Butler, Grayson, Breckinridge, Hardin, and Meade County. Elsewhere across Kentucky, scattered wind damage was produced by the main line of storms, with more favorably oriented segments of the line producing additional weak spin-up tornadoes. As the line of storms pushed east toward the I-75 corridor early in the morning on March 16th, there was a general weakening trend as MLCAPE values dropped to only around 100 J/kg across the Bluegrass. However, the portion of the line across southern Kentucky had access to slightly greater instability, resulting in additional instances of wind damage and a spin-up tornado in Clinton County. The line of storms eventually pushed into eastern Kentucky by around 3 AM on March 16th, with much cooler air rushing into the region behind the cold front.