Weather variability and rainfall pattern of Sidr, the post-monsoon cyclonic storm of 15 November 2007 in the Meghalaya Plateau, India

Atmospheric depressions sometimes initiate tropical cyclones in the pre- and post-monsoon season in the Bay of Bengal, which move to land and create havoc. Their intensity and pattern vary individually. After hourly monitoring of the weather parameters of cyclone Sidr of 15 November 2007 which created severe disaster and weather variability in the Bangladesh plains and hills of Meghalaya Plateau, India a noticeable depression of cool air masses in the starting phase of the cyclone was found, which created the atmospheric disturbance for a shorter time. As a result, the psychrometric index fell slightly with significantly higher thermal efficiency values in the starting phase of cyclone, thus inviting speedy wind with heavy rains in its last phase. The pattern of cyclonic rainfall is highly influenced by southerly (Northward) speedy winds, especially on the windward areas of the cyclone. Two-peaked pattern of diurnal rainfall was observed at Cherrapunji and its surroundings, which was the active path of Sidr on the windward slopes of the Plateau. On the other hand, leeward areas of the Plateau experienced one-peaked pattern of diurnal rainfall with lower intensity.