Tropical storms in the Indian seas both in the pre-monsoon and post-monsoon seasons are stronger than the south west monsoon systems in terms of intensity. Post-monsoon season is favourable for cyclogenesis of storms both in the Bay of Bengal and Arabian sea. However, the Arabian sea remains relatively dormant in comparison to Bay of Bengal.
Cyclones in Arabian Sea
On an average 1-2 tropical cyclones form over the Arabian sea each year and very few of these attain Very Severe Storm status. These systems need favourable upper level environment and warm sea surface temperature for growth. The strongest tropical cyclone in the record of the Arabian sea is cyclone GONU of 2007. It however, spared the Indian coastline and headed for Oman after recurvature causing massive destruction there.
Re-emergence of cyclones
There are also incidences of cyclonic systems generating independently on either side of Indian coastline in the seas. On numerous occasions, the one in Bay of Bengal after crossing peninsula emerges in the Arabian sea to become cyclone and threaten the Indian coast.
The life span of such systems obviously is far larger than those which form in Bay of Bengal and cross west coast in the northern latitudes.
Power of Cyclones
Severity of the system depends on the quantum of drop in pressure at the central region of the storm. Potential of a mature cyclone is to release energy equivalent of tens of hydrogen bombs.
Currently, the well-marked low pressure area over the Bay of Bengal off North Tamil Nadu- South Andhra Pradesh coast needs to be watched closely for any such development. The picture will become clear after 24-36 hours. Knowing the notorious track record of such systems, sharp vigil needs to be maintained for any adverse eventuality.
