Arabian Sea lets down monsoon watchers; focus shifts to Bay

The suspense over a low-pressure area spinning up in the Arabian Sea did not lift on Friday, the second day after the appointed day.

The formation of ‘low’ would have helped escalate the progress of monsoon towards the Kerala coast; but this is being effectively thwarted by opposing flows over the north Arabian Sea.

The original circulation in the higher levels, which was expected to descend and set up the ‘low,’ persisted over Lakshadweep and adjoining Kerala on Friday, India Met Department said.

A scenario being projected by varied models, including India Met Department, suggests that this circulation may push in a ‘pulse’ through the Gulf of Mannar into southwest Bay of Bengal off Tamil Nadu.

It may pick up some strength to set up a ‘low’ in the Bay and set itself on a course towards Myanmar-Bangladesh region.

This could bring the monsoon over Andaman and Nicobar where wind speeds are already picking in speed.

On the other hand, to the northwest of India, a crucial piece in the monsoon jigsaw puzzle - seasonal ‘heat low’ generated from intense heating of land - has failed to materialise.

The ‘heat low’ is the core around which the monsoon trough over the land builds up across the subcontinent, which in turns pulls in the monsoon current from the southwest.

Model predictions suggest that northwest India will be subjected to intense heating on Saturday and the ‘heat low’ may manifest itself briefly over northwest Rajasthan by the afternoon.

But this feature would have to become stabilised so as to set up the required pressure gradient from a region of high-pressure (around Kerala coast) to that with the lowest over Rajasthan for winds to blow in.

The monsoon runs up along this gradient after it makes its onset over Kerala coast - on May 30, with an error margin of four days to either side of the median, as the Met Department has predicted.