Stability Index and Thunderstorms over Nagpur

In this study, dependence of thunderstorm occurrences on stability index and the mean mixing ratio in the 850 to 700-mb layer has been examined. It is seen that most of the thunderstorms occur when the mean mixing ratio lies between 4.5 and 9.0 g/kg in March and April increasing to 6.5 to 13.0 g/kg in May and June. No thunderstorms occur when the mean mixing ratio of 850 and 700-mb layer is less than 3.5 g/kg.   Further, the difference of mixing ratios between 850 and 700-mb layers, which gives an idea of stability or instability in the 850 to 700-mb layer, was also examined for its influence on the thunderstorm formation and growth in a certain height group. The comparison of these heights with radar echo heights show a convincing proximity.