New Delhi: The southwest monsoon on Tuesday hit Kerala, three days before its scheduled arrival. The onset of monsoon over the southern state marks the commencement of the four-month-long rainy season in India. June 1 is the official onset date for the arrival of monsoon in the country and it takes more than a month-and-half to cover the entire country.
"The southwest monsoon has set in over the southern state of Kerala, three days ahead of its normal date," the India Meteorological Department (IMD) said in a statement.
The IMD has made a forecast of "normal" rainfall this season. It defines average or normal, rainfall as between 96 percent and 104 percent of a 50-year average of 89 cm for the entire four-month season beginning June.
According to the IMD, if after May 10, 60 percent of the available 14 stations - Minicoy, Amini, Thiruvananthapuram, Punalur, Kollam, Allapuzha, Kottayam, Kochi, Thrissur, Kozhikode, Thalassery, Kannur, Kudulu and Mangalore - report 2.5 mm or more rainfall for two consecutive days, the onset of monsoon over Kerala can be declared on the second day. This is one of the main parameters for declaring the arrival of monsoon.
Besides this factor, the westerly winds must be up to 15,000 feet above main sea level and outgoing long-wave radiation less than 200 wm-2 (watt per square metre) to declare the arrival of monsoon. All the necessary parameters were met following which the onset of monsoon over Kerala was announced, Mritunjay Mohapatra, Additional Director General, IMD said.
Monsoons deliver about 70 percent of India`s annual rainfall and are the lifeblood of its $2.5 trillion economy. The early arrival of monsoon rains typically enables farmers to bring forward sowing of crops such as rice, sugar cane, corn, cotton and soybeans.
In 2017, monsoon rains were 95 percent of the long-term average compared to forecasts of 98 percent. Before receiving average rains in 2016, India suffered back-to-back drought years for only the fourth time in more than a century.
(With PTI and Reuters inputs)