A great amount has been published on both tornado activity and hook echoes on radar. This paper discusses one popular tornado theory and explains the existence of the hook echo on radar. The tornado model used is that developed by the late Dr. Fred Bates. On the basis of the tornado theory, a steady-state storm develops with a rotating updraft at the center of the storm. The potential for tornadic development is on the convergent or windward side of the cell. The hook echo as viewed on radar, while not assumed to be the tornado itself, has an extremely high correlation with tornado occurrence or funnel cloud sightings. The question posed then is: What is this hook echo and how is it associated with the tornadic vortex. By using the model in the Bates Theory, a satisfactory conclusion can be derived.

Documented radar hook echoes and storm data for the years 1953-1966 were studied for clues to improve the tornado warning service. In 29 out of 33 instances, for which data were adequate for comparison, tornadoes occurred near the distal end or knob of observed radar hook echoes. The diameter of a circle which best fits or describes a radar hook echo and the speed and direction of movement of the parent storm cell for one hour are used to determine the size and limits of the tornado warning area. The method is advanced as a proposal for reducing the size of the tornado warning area when issued on the basis of an observed radar hook echo.

This report contains material taken from the available literature on identifying severe thunderstorms, hail, and tornadoes from radar echoes. Radar echo signatures indicating severe weather are consolidated for geographical areas and weather types to afford the radar meteorologist easy access to the findings of several investigators in the weather radar field. Information concerning X-band, S-band, and C-band radars is included.

This fully illustrated volume covers the history of radar meteorology, deals with the issues in the field from both the operational and the scientific viewpoint, and looks ahead to future issues and how they will affect the current atmosphere. With over 200 contributors, the volume is a product of the entire community and represents an unprecedented compendium of knowledge in the field.