The monsoon is preparing to enter an expansive phase over the next two three days and dropped signs to this effect both on the West Coast and the North-Eastern States during the 24 hours ending on Tuesday morning.
While the familiar monsoon playground of Cherrapunji in Meghalaya was pummelled with 40 cm of rainfall during this period, Agumbe and Karwar on the West Coast received 8 cm and 7 cm respectively.
The trigger for the rainfall was the intensification of an existing low-pressure area over the West-Central Arabian Sea (away from the West Coast) into being ‘marked,’ pulling in enhanced monsoon flows into the West Coast.
On the other side, rudimentary cyclonic circulations hovered off the Andhra Pradesh-Odisha coast and over the North Andaman Sea, pumping in oodles of moisture from the Bay of Bengal into North-East India.
While the ‘low’ over the West-Central Arabian Sea would drift away to Oman by Wednesday and become inconsequential, it would have effectively relayed the baton to counterpart circulations in the Bay.
Forecasts indicate that the two circulations will merge, become a composite low-pressure area and drive the monsoon to a high not seen since its onset was declared on May 30 over Kerala.
The emerging ‘low ’ could go on to become a monsoon depression and stay close to the Andhra Pradesh coast, pulling in monsoon flows both from the Arabian Sea and the Bay of Bengal.
This is expected to yield a strong monsoon current headed into East and Central India from this weekend.
A few models suggested that the ‘low’ may stay practically stationary along the Andhra Pradesh-Odisha coasts. This would only scale up rain manifold all over the the West Coast, Central India, and East and North-East India. The US National Centres for Environmental Prediction projected that the West Coast would receive a severe pounding from June 14 to 22 even as heavy rain lashes East India.
This signals the possibility that a second low-pressure area could form in the Bay — near the Head Bay, the sweet spot from the monsoon point of view — leading to an onrush of monsoon easterlies into East India and adjoining North-West India.