The Hindu Business Line : Bay whirl may come to interior peninsula’s aid

Thiruvananthapuram, July 16 The ‘problem areas’ of interior and west-central peninsula might just be able to get some rains before the month is out, as per latest predictions by international weather models.

Leading them is the Climate Prediction Centre (CPC) of the US National Weather Services, which sees ‘increased chances for rainfall across mainland India and the eastern Indian Ocean (the Bay of Bengal) during July 22-28.’ Almost the whole of the peninsula to the south of Gujarat, Madhya Pradesh, Chhattisgarh and Orissa will get covered by the late rains rustled up through the interaction of a Bay-generated circulation and an Arabian Sea trough.

And the forecaster has placed ‘moderate confidence’ in the scenario playing out to projections. There is increasing convergence among other models surveyed on a chain of rain events dotting the interior peninsula July 25 onwards. The anticipated collapse of a trans-peninsular trough in the extreme south should not be a worry now, thanks to the timely intervention by a westerly trough dipping into the northwest Bay.

A cyclonic circulation is forecast to be generated in its wake, which would hold the Bay end up and drive rains west-northwest from Orissa coast. It is forecast to interact with southwesterlies being steered by a resident Arabian Sea trough off the Karnataka-Konkan coast. The areas likely being kept out of coverage are north, northwest, east and northeast India, according to the CPC predictions based on initial conditions effective Monday. Forecasters were initially counting on a southern trans-peninsular trough to propagate rains into the interior but had given up hopes after learning about its shortened life.

‘LOW’ WATCH

The watch for a ‘low’ in the southeast Arabian Sea over the next three days is being maintained. The southern peninsular trough will be in place by Sunday after southwesterlies find their way around the peninsular tip. But the trough is seen getting a move to the west over interior Tamil Nadu the next day, and will stretch over Kerala into southeast Arabian Sea. It would slide entirely into the open Arabian Sea off the Karnataka coast later.

The Bay system would be triggered in the meantime, spreading spatially across mid-east and mid-central India and west Maharashtra even while digging the rear end deeper eastward into the Bay. Together with the Arabian Sea system, it will later set up a trough across north peninsular India.

IN AGREEMENT

This is more or less in agreement with what the CPC is looking at in terms of the footprint for the late-July rains. On scale of three (high, moderate and poor), the CPC has rated its confidence level in the eventuality as ‘moderate.’ The India Meteorological Department (IMD) said on Wednesday that the offshore trough from Karnataka coast to Kerala coast persisted, which would cause fairly widespread rainfall over coastal Karnataka, Kerala and Lakshadweep during next four days.

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