Monsoon sets in over Andaman sea two days early

New Delhi: The southwest monsoon has set in over most parts of the Andaman Sea and some parts of southeastern Bay of Bengal on Sunday—two days prior to its expected date.

Conditions are favourable for the advance of the southwest monsoon in the next 48 hours, according to India Meteorological Department (IMD).

The early onset over the Andaman and Nicobar Islands may not hold much significance for the arrival of the monsoon over Kerala, forecast for 5 June, four days later than normal. The June-to-September monsoon season is crucial for agriculture in India, where a majority of farmers depend on rain to irrigate their land. A delay in onset of the monsoon or poor rainfall will hurt farm production, accelerate inflation and delay an economic rebound in Asia’s third-largest economy.

“The timing of the onset of monsoon is important as it is indicative of later monsoon. If the onset is late, then it is not a good sign for the rest of monsoon because a general correlation has been seen between late onset and subsequent abnormalities in advance of the rainy season in the rest of the country, which can affect agricultural output,” said Abhijit Sen, member of the Planning Commission.

The normal onset date of monsoon over Kerala is 1 June. It marks the beginning of the country’s rainy season.

“If monsoon arrives on 5 June, it should not make much difference to the sowing of crops across the country,” Sen said.

Past data, however, suggests the absence of a direct link between the monsoon’s advance over the Andaman Sea with its onset over Kerala or that with the seasonal monsoon rainfall in the rest of the country, according to IMD.

“It has set over north Andaman Sea and southeast Bay of Bengal. It has set in 48 hours prior to its normal date, and it is expected to advance further towards west-central and east-central Bay of Bengal,” said a forecaster at Skymet, an independent tracker of the southwest monsoon.

“The reasons for the onset are the cross-equatorial flow becoming stronger, and there is also a cyclonic circulation over Bay of Bengal. This cyclonic circulation will become more organized and help in the advancement of the monsoon over Sri Lanka and finally the Indian mainland,” the forecaster said.

While the IMD has forecast a late arrival of the southwest monsoon over the Indian mainland, Skymet has forecast an early onset of the monsoon around 28 May.

After the southwest monsoon set in over most parts of Andaman sea and southeastern Bay of Bengal on Sunday, it advanced further into remaining parts of the Andaman Sea, and parts of southwest and east-central Bay of Bengal on Monday.

The southwest monsoon, which accounts for 70% of India’s annual rainfall, is the main source of irrigation for 235 million farmers, according to Bloomberg.

After setting over the Andaman Sea, the southwest monsoon is expected to make landfall in Kerala on 5 June, marking the beginning of rainy season in India.

It then advances further to the southern peninsula, northeast, through the east into north, central and finally west India—completing the advance of monsoon by 15 July, by IMD standards.

“Heavy rainfall can also be expected in Jammu and Kashmir, isolated parts of Himachal Pradesh and some parts of the southern peninsula and northeast India in the next 48 hours. Most of the rainfall taking place in the Indian mainland currently is because of the western disturbances,” said D.S. Pai, head of long-range forecasting division (LFD) at the IMD. Currently, heat-wave conditions are prevailing over some parts of Gangetic West Bengal and Bihar.