The Indian seas lie dormant for about 3 – 4 months from mid December to March. And now, the subcontinent is braving for the onset of pre- monsoon season. During this period, landmass and ocean both get charged to generate thunderstorm activity. Heat of the tropics invigorates these meso scale disturbances to result in violent thunderstorms over land and tropical storms over the seas.
The Indian seas have historically been the deadliest basin with several cyclones responsible for catastrophic damage, both, to the life and property. Satellite tracking and radar monitoring has helped scientists to predict accurately and extend adequate notice to adopt precautionary measures. However, the vagaries of weather remain elusive and continue to inflict challenges during large scale calamities.
Though, frequency of storms is more in the Bay of Bengal, in comparison to the Arabian Sea but severity takes almost equal toll on either side. Genesis mostly takes place in lower latitudes in the proximity of equatorial belt, in association with Inter- Tropical Convergence Zone (ITCZ), during the pre- monsoon season. More than 50% of the cyclonic disturbances (CDs) that form in the months of April and May intensify in to storms. A third of the cyclonic disturbances in the Bay and half the number CDs in the Arabian Sea intensify in to cyclones.
APRIL
Most of the Bay storms in this month originate over South and adjoining Southeast Bay of Bengal. They initially move in a northwest or north direction and later recurve towards northeast and strike Myanmar coast. The general direction of movement of storms in the Arabian Sea is similar to that of Bay storms. After recurving, they move towards Gujarat coast.
MAY
There is an appreciable increase in the frequency of storms from April to May. Most of the Bay storms originate between 10˚ and 15˚N, move initially in a northwesterly or northerly direction and then recurve towards the northeast. According to Skymet Meteorology Division, the whole of the east coast of India, the coastal areas of Bangladesh and Arakan coast of Myanmar are prone to storms in this month. A number of them are of severe intensity. In the Arabian Sea, the storms move in a northwest direction towards the coast of Arabia. A few move in a northerly direction to cross Maharashtra- Gujarat coast.
The next storm in the Indian seas, as and when it forms, will be named as Nanauk. The weather radars along the coastline on either side need to remain operational and work to their potential. These are the ‘lifeline’ for disaster mitigation and management.