The Indian Meteorological Department (IMD) formally announced the arrival of the southwest monsoon in the Bay of South Bengal, Southern Andaman Sea, Nicobar Islands and parts of the Northern Andaman Sea, which is one of the first arrival in the last seven years.
The average date of arrival of monsoon in this region is May 21, but this year it started at least a week ago i.e. on 13 May. Premature arrival has occurred in Nicobar Islands after two days of extensive to moderate to heavy rains, which is one of the primary parameters to announce the arrival of monsoon by IMD.
IMD said, “Southern Arabian Sea, Maldives and Komorin region, additional parts of the Bay of South Bengal, the entire Andaman and Nicobar Islands, the remaining parts of the Andaman and the Bay of Central Bengal remains favorable for the southwest monsoon to move forward in the next three to four days.”
Favorable conditions behind early start
Director General of Indian Meteorological Department Mrityunjay Mahapatra mentioned several factors responsible for this pre -start, such as:
- The minimum temperature in North India is higher than the average,
- Strengthening of western and eastern winds at many atmospheric levels,
- Pre-monsoon rainfall for more than 40 days in South India,
- Discrepancy of high pressure on the North-Western Pacific Ocean.
Mahapatra said, “All these indicators also point to Kerala to come before the monsoon time.” Model forecasts indicate that the monsoon will come in Kerala on 27 May, which is about five days before the normal 1 June.
Expectation of more rainfall than normal this year
This year, monsoon rainfall is estimated to be higher than normal, as the expected rainfall during June-September season should be 105% of the long-term average (LPA) 880 mm. The Indian southwest monsoon is the main rainfall, which provides more than 70% rainfall annually across the country.
