Airflow and Structure of a Tornadic Storm

Abstract

The thunderstorm that produced tornadoes near Geary, Okla., on 4 May 1961 is analyzed using data mainly from a vertically-scanning FPS-6 radar. The storm configuration was remarkably similar in many respects to the severe Wokingham hailstorm in England, analyzed by Browning and Ludlam. Each attained a fairly steady state during which certain characteristic features were displayed. Most important of these was the vault, a region of low reflectivity beneath the highest parts of the storm which is believed to be symptomatic of an intense and persistent updraft. This and other features of its structure are analyzed in conjunction with nearby soundings to give a model of the airflow associated with the Geary storm. Like the Wokingham storm, it comprised a persistent updraft which entered and left on the downshear side. This kind of airflow is believed to be representative of an important class of persistently intense cumulonimbus which travel within a strongly sheared environment.