Cloud-to-ground lightning in a tornadic storm on 8 May 1986

Abstract

In the mesocyclone that spawned the tornado, low-level cyclonic shear peaked as the first tornado dissipated and a second tornado began. As low-level cyclonic shear initially increased, negative cloud-to-ground lightning flash rates also increased, reaching a peak of 11 min-1 a few minutes after the peak in cyclonic shear. During this period lightning strike locations tended to concentrate just north of the mesocyclone, near and inside a 50-dBZ reflectivity core. As cyclonic shear decreased from its peak during and after the second tornado, negative ground flash rates also decreased, and strike locations became more scattered. Positive ground flashes began just before the storm became tornadic, and positive flash rates peaked during the tornadic stage of the storm. -from Authors