The Hindu Business Line : Fresh ‘low’ expected to boost monsoon flows

Thiruvananthapuram, May 16 Thursday’s well marked low-pressure area over east-central and adjoining northeast Bay of Bengal has weakened overnight into a conventional ‘low’ and lay over the coastal areas of Myanmar and adjoining northeast Bay. The system is likely to move northeast and away from India’s territorial waters, says an update from India Meteorological Department (IMD) on Friday.

The Bay has been forecast to become active again around May 24 when a fresh cyclonic circulation takes shape over the north-central quadrant. The system would descend to lower levels to set up a ‘low’ in due course.

Monsoon flows are tipped to get fresh boost under the ‘pull’ effect of the system, said a medium-range outlook from the Ministry of Earth Sciences. But, as has been the case with the two predecessors, this too would get appropriated by a western disturbance dipping low into the Head Bay.

It would be guided in a north-northeast direction to be ultimately deposited over the Bangladesh coast around May 27.

Monsoon flows are seen holding themselves together right from the genesis of the system, given that no big storm is forecast to develop concurrently in the South China Sea or the Western Pacific.

NORMAL MONSOON

Meanwhile, the latest update from the International Research Institute (IRI) for Climate and Society at Columbia University seems to buttress the case for a ‘normal monsoon’ for India despite a weakening hold of the La Nina.

While no region is forecast to return a deficit during the June-September season, west-central India (especially north and west Maharashtra, south and west Madhya Pradesh) and fringes of northwest India are tipped to receive surplus rainfall in July, August and September. The onset phase in the northeast will see an active spell, while it is likely to be muted along the Kerala coast.

This outlook is more or less in agreement with what is expected from the convergence of a La Nina (colder counterpart of El Nino) and a negative India Ocean Dipole (IOD, represented in sea-sawing of sea surface temperatures over the equatorial Indian Ocean).

CLIMB-DOWN

The European Centre for Medium-Range Forecasts (ECMWF) has indicated a progressive drying up along the southwest and northeast gateways as the monsoon forayed inland, resulting in palpable deficit over these areas. Overall, the weakening hold of La Nina is reflected in the precipitation levels forecast, which have seen a climb-down from those made a few months back.

The IMD said on Friday that lower level winds would turn from northwesterly to westerly over the south and adjoining Arabian Sea from May 19. This will set the right wind profile for the monsoon to break over Kerala.

On Friday, a cyclonic circulation parked over the northeast was expected to trigger scattered to fairly widespread rain or thundershowers over Nagaland, Manipur, Mizoram, Tripura, eastern parts of Arunachal Pradesh and Assam during the next two days. Isolated thunder squall is likely over Orissa, West Bengal, Sikkim and Rajasthan.

Thunderstorms and squalls will continue their destructive run over the Indo-Gangetic plains for four days from Sunday as a fresh western disturbance drifts in from the northwest.

The heating of the land was still skewed to the southeast, with Machilipatnam in Andhra Pradesh recording the maximum temperature of 45.4{ring}C on Friday.

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