Some Aspects of Thunderstorm over India during Pre-Monsoon Season: A Preliminary Report-I

Thunderstorm, resulting from vigorous convective activity, is one of the most magnificent weather phenomena in the earth’s atmosphere. The severe thunderstorms associated with thunder squall, hail storm, tornado, flash flood and lightning cause extensive damage and losses to lives and property. A common feature of the weather during the pre-monsoon season over the Indian region is the outburst of severe local convective storms. This paper presents on the aspects of the realized significant weather phenomena thunderstorm, which is supported through the analyses of thermodynamic instability indices based on the radiosonde and rawinsonde (RS/RW) ascent products from India Meteorological Department (IMD) for the pre-monsoon season for different identified cities of SAARC STORM project region of India. Doppler Weather Radar (DWR) images and Skew-T diagrams are also analyzed which support the thunderstorm activities in different locations of India. The convective available potential energy (CAPE) and convective inhibition (CIN) energy show the favorable conditions for the thunderstorm to occur in some of the identified stations; however, due to physiographic uniqueness of Indian subcontinent, the values of CAPE, CIN and other thermodynamic parameters show different values in different stations. Moreover, the variation in threshold values of CAPE in different regions makes thunderstorm forecasting difficult which may add uncertainty to loss estimation for risk assessment. A simple outline on thunderstorm risk assessment model development steps are also highlighted as a future work for the quantification of losses, so that the likely probability of occurrences of events with their frequency, location, severity and extent of losses can be modeled and accessed ahead of time for the betterment of the society.