A weather system - low-pressure area or depression, or even a cyclone - brewing in Southwest Bay of Bengal, off Sri Lanka, could have a major influence on precipitating this year’s Southwest monsoon.

 

India Meteorological Department identified a cyclonic circulation, the rudimentary form of a building storm, hanging over the suspect area (off Sri Lanka and southeast of peninsular India).

 

As of now, the system has got everything going for it to grow in scale and size – including a very warm pool of water measuring 32 deg Celsius and above and least resistance for the storm tower to erect itself thousands of feet into atmosphere. Almost half of the Bay of Bengal too has warmed up, if not to this level.

 

Warm seas provide the ‘feed’ (in the form of convection, moisture and cloud formation) for a storm to grow in strength and chart a move across warm tropical waters, helped by steering winds.

 

Weather maps showed that the Southeast Arabian Sea to the southwest of the peninsula too has started to warm up, just in time to host the monsoon current in case gets pulled in by the storm in the Bay.

 

The Bay holds the largest pool of warmed-up waters that can facilitate the run of the storm, helping it to thrive on incremental moisture and cloud-building.

 

Pre-monsoon storms in the Bay have a tendency to track east-northeast and head towards Myanmar/Bangladesh for a landfall.

 

In fact this is how an experimental storm tracker featured by the Climate Prediction Centre of US National Weather Services sees it.

 

The European Centre for Medium-Range Weather Forecasts is less assertive and sees the storm (only a low-pressure area?) striking a pause to the north-northwest, off Chennai, by May 13.

 

But US Naval models show a destructive storm in the making, which is parked dangerously close to Northeast Sri Lanka and Southeast Tamil Nadu around this time, the Hindu reports.