Monsoon sets in over Kerala

The Met Department has declared the onset of monsoon over Kerala on Saturday.

It represented the second day in the eight-day window (error margin) for the onset fixed by the Met Department to either side of the mean of June 3.

WIDESPREAD RAIN

The 14 rainfall monitoring stations in the State reported fairly widespread showers for the last two days, a mandatory criterion for declaring the onset.

This came a day after a Japanese research agency warned that the monsoon could end up below normal due to heating abnormalities in the Indian Ocean.

In contrast, conditions in the Equatorial Pacific, the other ocean region with a significant say on monsoon behaviour, were forecast to remain neutral or even mildly favour the June-to-September season.

But this may not be sufficient to neutralise the effects of a negative Indian Ocean Dipole phenomenon in which the East of the basin warms up relative the West.

GETS DIVERTED

What this means is that monsoon convection and cloud-building takes place in the East Indian Ocean (off Indonesia) and gets diverted away from mainland India.

On the other hand, the positive phase of Indian Ocean Dipole in which the West basin warms up more than the East has been found to help Indian monsoon.

Earlier this week, the Australian Bureau of Meteorology too had observed development of conditions that favoured a negative Indian Ocean Dipole.

The Met Department said the Westerly to West-southwesterly monsoon winds were clocking a strong 40 to 50 km/hr and were observed on Saturday to a height of up to 4.5 km.

The monsoon has since advanced into entire South Arabian Sea; entire Kerala; parts of Central Arabian Sea; parts of coastal and South Interior Karnataka; most of Tamil Nadu; and parts of Southwest and West-central Bay of Bengal.

On Saturday, the northern limit of monsoon, which links together farthest points covered by its leading edge, passed through Mangalore, Mysore, Salem and Cuddalore.

Outlook for next two days said that conditions are favourable for further advance of monsoon into some parts of Central Arabian Sea and Karnataka; remaining parts of Tamil Nadu; parts of South Andhra Pradesh and some more parts of Bay of Bengal.