Pulse from typhoon 'Mangkhut' in Bay may grow as a storm

A rudimentary cyclonic circulation has reached the Gulf of Martaban, an arm of Andaman Sea to the South of Myanmar, to set up the next low-pressure area in the adjoining Bay of Bengal. Global model forecasts indicate that it would grow on to become a storm (depression/deep depression) and impact North Coastal Andhra Pradesh/Odisha coast in due course.

Gift from 'Mangkhut'

India Met Department (IMD) has already put the evolving system under watch for intensification, though without saying to what extent it would gain strength. In fact, it has warned of adverse sea conditions likely over the Central Bay and over Andaman & Nicobar Islands during the next four days.

Fishermen have been advised not to venture into and around Andaman & Nicobar Islands during the next three days and along West Bengal and Odisha coasts until Thursday. The circulation in the Bay is a 'pulse' tossed in by erstwhile category-5 super typhoon Mangkhut, now re-classified as a typhoon, after it hit northern Philippines and lost intensity.

Agency reports said Mangkhut killed at least 30 people in the Philippines as it obliterated homes and crops and caused massive flooding. After hitting the northern Philippines island of Luzon early yesterday, 'Mangkhut' is now on course to plough into China’s southern coast.

Trough stirs itself up

'Mangkhut's' high winds ripped the roofs off houses in Luzon, and pulled down trees and electricity pylons. Accompanying rains rains caused fatal landslides and flooding.

Back home, the India Meteorological Department said on Sunday morning that the rain-setting monsoon trough over North India runs close to the Himalayan foothills but its eastern end has now dipped into the East-Central Bay.

The trough running close to the foothills signals a weak phase of the monsoon over large parts of the country, and can breathe itself back to life only with some activity building in the Bay. This is what happening now, with the fresh circulation in the Bay likely concentrating as a 'low' and strengthening, which, as per US National Weather Services outlook, might grow further into a storm.

As if on cue, the circulation has on Sunday moved in from the Gulf of Martaban into the East-Central Bay. The 'low' may develop over Central and adjoining North Bay in two day's time. Already, another circulation has set up a perch over North Coastal Andhra Pradesh, with a trough running down to North Tamil Nadu. This, though, could break up after the 'low' gains strength.

Track over land

The IMD has lately said that the 'low' after crossing coast, could intensify further and move across Odisha, Chhattisgarh and Madhya Pradesh between September 21 and 24. It will trigger enhanced rainfall activity over Central India and the plains over North India, even interacting with an incoming western disturbance over Delhi and neighbourhood.

Satellite pictures on Sunday afternoon showed that rain-bearing clouds borne out of the building activity in the Bay have spread out along the East Coast of India. Widespread rainfall with isolated heavy to very heavy falls is forecast over Central and adjoining Peninsular India between September 21 and 23.

It would be fairly widespread to widespread over East and North-East India and isolated over the rest of the country outside West Rajasthan, Saurashtra and Punjab where dry weather is likely to prevail. In this manner, the fresh 'low' in the Bay would interfere with the process of withdrawal of the South-West monsoon from North-West India, likely dragging it into early October.

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