Beta drift [?] or backward drift

Cyclones in north Indian Oceans [i.e in Bay of Bengal &  Arabian Sea which are the real extension of Indian Ocean in the east and west side of India] generally tend to move in North & north westerly direction.  That is why the eastern coast of India is more prone to cyclone hit than its western counterpart.  Similarly recarvature i.e movement in NEly direction is also a common feature of a cyclone movement.  But there is rare evidence that the cyclone drifted south west wards. Will this drift be caused by the advection of the background potential vorticity field by the storm circulation?

 Because,

[1] The SST from Cape Comorin to Puducherry, especially in Mannar Bay and in  Coramandal coast at least between Vedaranyam and Marakanam is relatively high than compare to elsewhere in the Bay.

[2] The horizontal warm air advection in the above said coastal stretch will lead to the formation of vortex.

[3] This formation may be in SWly direction to the current location of VSCS.

                                                                                                    

Beta Drift

The drift of a tropical cyclone through the large-scale background wind in which it is embedded is known as Beta drift. The drift is caused by the advection of the background potential vorticity field by the storm circulation. Beta drift generally causes tropical cyclones to move pole ward and westward relative to the motion they would have if the background potential vorticity field were unperturbed by the storms. This drift speed is generally around 1–2 m/s.

Courtesy:  American Meteorological Society. .