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.

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