Under the influence of cyclonic circulation persisting for over 36 hours, a low pressure area has formed over South Andaman Sea and adjoining Southeast Bay of Bengal. A broad cyclonic circulation extending up to mid tropospheric levels is marked. Convective cloud cluster of tall clouds as a foremost indicator of likely depression shortly, is covering Andaman & Nicobar Islands. Heavy rains have lashed the region yesterday and expected to continue for 2 more days. All these precursors, joined together are throwing enough indications of tropical storm in the area in the next about 48-72hours.
Ocean heat potential is a major contributor towards growth of storms. Entire Bay of Bengal is hotter than normal and the sea surface temperature is in excess of 30°C. Low pressure is emerging over an area between 8°N and 12°N, legible enough to draw support of Coriolis Force. Vertical wind shear remains moderate and unlikely to suppress further expansion. Climatological features suggest cyclone formation over the area, may be earlier than expected.
While formation of a tropical storm looks assertive, its further trajectory continue to be obscure and vague, at this point of time. More clarity and confidence awaits system’s intensification to a depression, wherein the central position will become precise and decisive. The steering current dictated by the axis of sub tropical anticyclone in the higher tropospheric levels is expected to be more revealing over next 48hr. Currently, these are the predicaments against which the cyclonic disturbance is battling over the warm waters of Andaman Sea.
The tropical storm, as and when forms, will be named ‘Asani’. The name this time is assigned by Sri Lanka and literally means ‘wrath’. Candidly speaking, the storm as and when developed, will be precariously placed over central parts of Bay of Bengal. The dichotomous situation will leave the storm with multiple options. The excessive heat potential of sea surface can increase the severity, more than gauged by the models.
The probability of the storm coming closer to North Andhra Pradesh and South Odisha coast is growing large. Thereafter, the statistical records of climatology leaves bifold trajectory for the cyclone. The 1st scenario takes the storm for a direct strike over bordering areas of North Coastal Andhra Pradesh and South Odisha.
The alternate trajectory, albeit equally strong, can make the storm recurve to run parallel to the coastline of Andhra Pradesh and Odisha and head for West Bengal and Bangladesh. In this case, head Bay of Bengal, being relatively colder and proximity of land debilitates the storm and erodes its structure. An observation period of about 48-72 hours will be needed to announce a clear verdict.