A Litton Systems 500-kHz, SPARSA/S, 64-channel, thunderstorm-sferics sensor is coupled to the PPI scope of a 10-cm wavelength weather radar. Short vectors protrude from the center of the PPI scope indicating the direction and count rate of sferics discharges. The sferics sensor is thresholded to detect activity within approximately 200 n mi which is equal to the useful range of the weather radar. Thus, the sferics sensor is used to identify thunderstorm precipitation echoes on the radarscope and the combined presentations are photographed on time-lapse 35-mm film. The results of three years of investigations of summer thunderstorms in South Florida are presented. Radar PPI and directional 500-kHz sferics data within 200 n mi of Miami are analyzed for 1967–69. During the years 1968 and 1969, three-dimensional radar data to 100 mi range are also included. Relationships between thunderstorm sferics activity and precipitation echo size, height, intensity, life cycle, and geographical distribution are given. In most cases, the first sferics activity war, observed after the precipitation echoes became radar-detectable; the activity intensified as the echoes grew in size and intensity.