INTRODUCTION

Keeping in to account the devastations caused by the severe thunderstorms during pre-monsoon months of March-April-May over different parts of India and particularly the northern and northwestern region, Ministry of Earth Sciences took a time targeted development work under the chairmanship of Secretary, MoES. A brain storming meeting was held in 1 June 2018 and subsequently a MoES working group has been formed to develop the tools of predicting thunderstorm occurrence as well as lightning flash, lightning probability, heavy rain, gusty wind etc. with 24 hour lead time and outlook with 48 hour lead time.

Under this new initiative, scientists from IITM, IMD and NCMRWF worked together in coordination and a holistic tool for nowcast (up to 1 hour), for 24 hour forecast from high resolution model and 48 hour outlook from high resolution global model thunderstorm specific products, have been developed.

For improving the nowcast of thunderstorm location and associated lightning, the high resolution satellite observations, lightning sensor observations (from IITM and IAF) and the RADAR observations have been merged to develop a user friendly high spatio-temporal frequency based operational product. For 24 hour ahead prediction, high resolution mesoscale models of IITM and IMD have been utilized to develop thunderstorm specific products and provide the guidance at district level. To get 48 hour ahead thunderstorm guidance, the Global Forecast System (at 12.5 km spatial resolution), has been utilized to develop several thunderstorm specific products.

Based on all the above products IMD issues thunderstorm nowcast for around 450 stations and 24 hour ahead thunderstorm forecast guidance for the country as a whole. To better communicate the prediction and warning of thunderstorm to public/society and stake holders, a dedicated website has been prepared where all these information is available with latest update and details.

During 2019 pre-monsoon season of March-April-May, this new prediction tool has been utilized and the thunderstorm forecast guidance over different parts of India has been found to be timely and accurate that has helped in saving public life and properties.