Southwest monsoon made an early onset over Kerala and northeastern region on Thursday, setting the stage for the four-month rainy season crucial for India's agriculture-based economy.
Weather scientists said cyclone Remal, which ripped through West Bengal and Bangladesh on Sunday, had pulled the monsoonal flow to the Bay of Bengal, which could be one of the reasons for early onset over the northeast.
On May 15, the weather office had announced the onset of monsoon over Kerala by May 31.
The simultaneous onset of monsoon over Kerala and the northeast is quite rare and has happened on four occasions earlier,? in 2017, 1997, 1995 and 1991. "Southwest monsoon has set in over Kerala and advanced into most parts of northeast India today, the 30th May, 2024," the India Meteorological Department said.
The weather office said southwest monsoon has also covered most parts of the northeast region including entire Nagaland, Manipur, Mizoram, Arunachal Pradesh and parts of Tripura, Meghalaya, and Assam.
Between 1971 and 2024, the earliest onset of monsoon over Kerala was in 1990 when the annual rains reached the coastal state on May 18. The onset of monsoon over Kerala happened on May 22 in 1999, and on May 23 in 1974 and 2009. Kerala has been receiving heavy rains for the past few days resulting in a surplus May rainfall, the weather office data showed.
The normal monsoon onset date for Kerala is June 1 and for Arunachal Pradesh, Tripura, Nagaland, Meghalaya, Mizoram, Manipur and Assam is June 5.
The IMD declares onset of monsoon over Kerala when over 14 stations in the state and neighbouring areas receive 2.5 mm or more rainfall for two consecutive days anytime after May 10, the Outgoing Longwave Radiation (OLR) is low, and the direction of the winds is southwesterly.
The monsoon is critical for India's agricultural landscape, with 52 per cent of the net cultivated area relying on it. It is also crucial for replenishing reservoirs critical for drinking water, apart from power generation across the country.
June and July are considered the most important monsoon months for agriculture because most of the sowing for the Kharif crop takes place during this period.
El Nino conditions are prevailing at present, and La Nina may set in by August-September, scientists said. El Nino -- the periodic warming of surface waters in the central Pacific Ocean -- is associated with weaker monsoon winds and drier conditions in India. La Nina -- the antithesis of El Nino -- leads to plentiful rainfall during the monsoon season.
