Observations of High Densities and Rates of Positive Flashes in Summertime Thunderstorms in Brazil

Observations of summertime thunderstorms in Brazil in 1993 indicate periods with the predominance of positive cloud-to-ground lightning flashes. The periods present high density (average value of 0.66/km2h.) and high hourly rate (average value of 478/h) of positive flashes. In most cases, they occurred at or near the beginning of the storm's cloud-to-ground lightning activity and had duration of about 2.Sh.