Much progress has been made in the past decade in understanding the production of positive ground flashes in severe storms. Many studies have utilized three-dimensional lightning mapping arrays (LMAs) to reveal the inverted polarity charge structure thought to support positive ground flashes. The internal charge structure of storms dominated by negative polarity ground flashes has not received as much attention from the perspective of LMA data.

Two supercell thunderstorms are compared in this study. One storm from Oklahoma lowered predominantly positive charge to ground, while another from Alabama lowered predominantly negative charge to ground. An interpretive framework is used that distinguishes between charging regions and regions of charge, and relates both to conventional supercellular structural features and their microphysical history as observed in coincident weather radar data.