North-East monsoon likely in two days, says Met Dept

A low-pressure area is expected to form over South Bay of Bengal by Monday, to be followed next day by the onset of the Northeast monsoon over South Peninsular India.

The India Meteorological Department (IMD) has put the low-pressure area under watch for intensification.

HEAVY RAIN

It has warned that isolated heavy rain may lash Kerala, south coastal Andhra Pradesh, Tamil Nadu and Puducherry during next two days.

Rain or thundershowers may break out at many places over coastal Karnataka, Kerala, south coastal Andhra Pradesh, Tamil Nadu, Puducherry and Lakshadweep.

A few places over south interior Karnataka, north coastal Andhra Pradesh and Rayalaseema also may receive rain.

The North-East monsoon is expected to materialise simultaneously as predecessor South-West monsoon completes its most successful rain in decades together.

NO CONSENSUS

Meanwhile, consensus still eludes meteorologists on what might have caused the South-West monsoon to fire on all cylinders this year and end with a surplus of six per cent.

The four-month season has had to fight a negative Indian Ocean Dipole event that mimics the ENSO (El Nino-La Nina) event. The dipole event may have just ended, an Australian Bureau of Meteorology review confirmed.

It ran almost parallel but failed to make an impression on the monsoon, fed as it was by the humungous supply of moisture from the nearby seas.

This ensured that the Bay of Bengal was kept busy churning out helpful low-pressure areas and even enhanced weather systems to generate rain over land.

FEWER TYPHOONS

In this context, a group of researchers argue that the activity in the Bay had to more with the less than productive season in the North-West Pacific to the East.

South-westerly flows headed into the North-West Pacific got directed instead to the Bay of Bengal.

The London-based Tropical Storm Risk Group had in early August come out with a forecast for fewer-than-anticipated storms being generated in the North-West Pacific.

Adam Lea, a scientist at Tropical Storm Risk Group, informed Business Line that the key factor behind below-normal cyclone season there was the unusual lack of activity through to early August.

Only two typhoons had formed in the North-West Pacific until August 8. Since 1965, only five years (1970, 1975, 1995, 1998 and 2010) have had two or less typhoons form by the August 6.

“Thus our August forecast had been lowered to 20 per cent below the 1965-2012 climate norm…” Lea wrote to Business Line .

> vinson.kurian@thehindu.co.in

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