Comparative Study of Severe Thunderstorms of 15-16 April 2020 and 25-26 June 2020

Abstract

High impact severe weather events like thunderstorms are associated with strong winds, dust, thunder, lightning, heavy rainfall, hail etc. Such events have devastating consequences particularly leading to aviation hazards, loss of life and damage to property, vegetable crops and food. A severe thunderstorm had caused large scale damage to life and property over Sub-Himalayan West Bengal, Sikkim and North-eastern states during 15-16 April 2020. Similarly, a fusillade of lightning strikes associated with intense thunderstorm spread across the two states of Bihar and Uttar Pradesh on 25-26 June 2020 killed more than 100 people. In the present research, a comparative study has been carried out by investigating synoptic, thermodynamic and dynamical features leading to these two intense systems. Global Forecast System model at 12 Km resolution along with the Weather Research and Forecasting model version 3.6.1 at 3 Km resolution have been used for the analysis of operational forecasts of these two cases i.e. 15-16 April and 25-26 June 2020.
The low-level convergence associated with the cyclonic circulation of strong moist winds from the Bay of Bengal region was responsible for the severe thunderstorm of 15-16 April 2020. Whereas the event of 25-26 June 2020 during the monsoon period, was associated with low level convergence over Bihar and Uttar Pradesh supported by high values of low-level humidity. The global and regional model (GFS and WRF) forecasts indicated the favourable environmental factors for the occurrence of thunderstorms in both the cases.