India Met Department has put out a watch for a low-pressure area in the Arabian Sea around the Lakshadweep Island off the Karnataka-Kerala coast.
Forming of 'low’ during this time of the year when the southwest monsoon has exited the mainland or is in the process of doing so, needs special watch.
This year, the monsoon withdrawal has been delayed with most of northern part of India having been brought under the grip of drier northwesterly winds.
In the South, the monsoon has been offering some resistance to the invading northwesterlies, and the ‘low’ will form in the sea where the two winds converge.
According to most weather models, the ‘low’ will intensify in strength and graduate to become a monsoon depression/cyclone off the Karnataka-Konkan coast.
This transformation is expected to take place over the next two-three days and into the weekend, as per projections by these models.
October cyclones
Given the transition period of southwest monsoon to northeast monsoon, October is a month that has witnessed tropical cyclones in the Arabian Sea/Bay of Bengal.
The Indian region gets affected by cyclones in two different seasons - pre-monsoon (April and May) and post-monsoon (October and November).
This is a unique feature of the geographic region and increases its vulnerability. It is the increased wind shear that prevents cyclone formation during a monsoon.
During the monsoon, the winds change in direction and speed with height producing ‘shear’ and this unsettles building storm structures.
This is reversed during the transition period when wind shear gets reduced, allowing the storms to build their structures in a proper fashion and grow in strength.