The Evolution of Tornadic Storms

Abstract

A life cycle classification for severe local storms is proposed, which adds a fourth stage, the quasi-steady SR Mature Stage, to the well-known Byers-Braham classification. A combined analysis of the surface weather and radar echoes from three neighboring severe local storms reveals that each storm went through a similar, well-defined metamorphosis at the onset of its SR Mature Stage. The distinctive character of this stage is attributed to the rotational properties of the updraft, which in the storms studied developed when the updrafts had become vigorous enough to produce giant hail.