Monitoring Convective Activity over India During Pre-Monsoon Season-2013 under the SAARC STORM Project

Abstract

SAARC STORM Project has been carried out as a multi-year observational-cum modelling campaign with an objective to build appropriate operational early warning systems for highly damaging severe thunder storms over various parts of India. The programme started with a pre-pilot phase in the year 2006 and was originally conceived for understanding the severe thunderstorms known as Nor'westers that affect West Bengal and the North eastern parts of India during the pre-monsoon season. Since rest of India and the neighbouring south Asian countries are also affected by thunderstorms, the STORM programme has now included all South Asian countries under the South Asian Association for Regional Cooperation (SAARC). The programme was monitored at IMD, New Delhi. Data from around 500 IMD manned surface observatories have been used for monitoring and recording the weather all over India. In addition to the above; rainfall activity was monitored through a network of about 2000 raingauge stations spread across the country. The frequency of thunderstorms in Northeast India was the highest in the night while in East India the frequency was highest in the evening. The Sub Himalayan West Bengal and Sikkim subdivision got most of the thunderstorms in the night while remaining states Odisha, Bihar and Gangetic West Bengal got thunderstorms during evening. Thunderstorms are recorded generally on all days in April and May in Northeast India and the dew Point temperature at 850 hPa was more than 5°C on most of the days. Southern Peninsular Region and Northwest India got most of the thunderstorms in the afternoon and evening. CAPE values for New Delhi (0000UTC RS/RW ascent) were found to be very low (<500) on all days during April and May and insignificantly correlated with TS activity over the region.