Observations of Vertical Motions and Particle Sizes in a Thunderstorm

By means of a vertically pointing pulsed-doppler radar, observations were made of a growing thunderstorm moving overhead. An updraft having a maximum speed exceeding 19 m sec−1 was observed in the upper part of the cloud. The character of the vertical velocity distribution supports earlier speculations about the pattern of vertical velocity near the top of an updraft. Inferences are made of the characteristics of precipitation in this cloud. The analyses lead to the conclusion that there were hail particles in the cloud. Although maximum echo intensity occurred in regions where hail particles with diameters of about 1 cm were present, maximum backscatter of radar power came from particles about half this size.