A preliminary study on pre-monsoon summer thunderstorms using ground-based total lightning data over Gangetic West Bengal

This paper presents the preliminary results of observation of total lightning characteristics of pre-monsoon thunderstorms of 2018 over Gangetic West Bengal around Kolkata. Mainly, the analysis results of total lightning associated with pre-monsoon moderate and severe thunderstorm events, locally known as Kalbaishakhi or Nor'wester, are presented. The total lightning data include both in-cloud and cloud-to-ground lightning flashes and are obtained from the Earth Networks Total Lightning Network. Most of the events were multi-cellular in nature as inferred from lightning data. The total lightning count over an area of 10 km radius around the wind sensors, increased rapidly about similar to 10-40 min before the onset of high wind on the surface. Primarily, total lightning count >= 30 per minute was found to be associated with the Nor'westers which produced maximum surface wind speed above 50 km/h.