ELECTRICAL STRUCTURE AND UPDRAFT SPEEDS IN THUNDERSTORMS OVER THE SOUTHERN GREAT-PLAINS

We have acquired 11 balloon soundings of the electric field and thermodynamics in large and sometimes severe and tornadic thunderstorms over the southern Great Plains. The ascent rates of the balloons were used to divide the soundings into weak and strong updrafts. All 11 soundings had magnitudes of charge densities and thicknesses of charge regions similar to those reported previously in small thunderstorms. The five weak-updraft soundings had complex charge structures of 7-9 charge regions below 10 km altitude. The magnitude of the maximum measured electric field in these soundings was 100-150 kV m(-1). The four soundings in strong updrafts had balloon ascent rates of at least 15 m s(-1) for at least 1 km. These soundings had simpler electrical structures of 3-5 charge regions below 10 km altitude. Their maximum measured electric fields ranged from 85 to 130 kV m(-1). The data may support an earlier hypothesis that charge is elevated in strong updrafts. In addition, the data may suggest that simpler charge structures are associated with proximity to strong updrafts rather than with different storm types.