A CLIMATOLOGY OF VERY HIGH ALTITUDE RADAR PRECIPITATION ECHOES.
Air Force Surveys in Geophysics no. 207,
AIR FORCE CAMBRIDGE RESEARCH LABS L G HANSCOM FIELD MASS
Pagination or Media Count:
The frequency and percent occurrence of radar precipitation echoes from 50 to at least 70 kft over the United States is presented. Analyses of six years of data from a 31-station WSR-57 weather radar network indicate that probabilities of convective clouds are greatest over three regions the Gulf Coast a relatively narrow band northward through the central United States and Florida. Largest probabilities at all levels and locations occur generally in summer, varying from May and June in central areas to August over south and southeast coastal regions. Based on mid-season months, maximum mean monthly probabilities are greater than 13 at 50-55 kft and nearly 1-12 at 60-65 kft near New Orleans in summer. In addition, precipitation echoes have been reported up to at least 70 kft at eight locations through the central United States in May through September, and up to 60 kft at a few Gulf coast stations in winter. Diurnal fluctuations at altitudes above 50 kft are such that largest probabilities are between 1600 and 2100 LST in all regions, with values approaching 10 at New Orleans and 7 at Tampa on an annual basis. Values for July are roughly three times larger than these at all stations. Author