Hail Determination by Radar Analysis1

Radar reports from 17 radar stations are correlated with hail reports for the 4-month period April through July 1956. The relationship between radar detection of precipitation at long ranges and the occurrence of hail is studied. Fifty percent of all echoes reported a t ranges of 135 n. mi. or greater are found to have contained hail. Results of an operational test of the method of analysis are given. Sixty-seven percent of all cases of ¾-inch or larger hail reported in the test area are found to have been identified by the term “Hail Indicated” in hourly radar summaries by the Radar Analysis and Development Unit at the time the hail was occurring.