Preferred type of cloud in the genesis of severe thunderstorms — A soft computing approach

The present paper attempts to identify the type of low level clouds preferred for the genesis of severe thunderstorms over Kolkata (22° 32′, 88° 20′) during the transition period of pre-monsoon season (April–May). Soft computing technique in the form of Rough Set Theory is adopted for recognizing the pattern of low level clouds. Different possible types of clouds are explored with ten years data in the present study for the occurrence of severe thunderstorms over Kolkata confined within the northeastern part of India (20° N to 24 ° N latitude, 85 ° E to 93 ° E longitude). The results show that for the occurrence of severe thunderstorms over Kolkata the preferred type of low level cloud is cumulonimbus and the transition from stratocumulus to cumulonimbus is a significant conversion of cloud type. The result further reveals that the formation of cumulonimbus cloud at 06 GMT is an extremely favorable condition for the genesis of the severe thunderstorms over Kolkata during the pre-monsoon season.