Southwest monsoon lands in Kerala: IMD

New Delhi After a delay of two days, the southwest monsoon made an onset over Kerala on Thursday, marking the commencement of the four-month rainfall season in the country, the India Meteorological Department (IMD) said.

"The southwest monsoon has made an onset over southern parts of Kerala," said IMD Director General Mrutunjay Mohapatra. The normal onset date for southwest monsoon over Kerala is June 1. Southwest Monsoon is likely to advance into remaining parts of south Arabian Sea and some parts of central Arabian sea, remaining parts of Kerala, Lakshadweep, some parts of Tamil Nadu, Puducherry, coastal and south interior Karnataka, Rayalaseema, and south and central Bay of Bengal during the next two days, the IMD said.

This is the third time in the last six years that monsoon arrived late. In 2016 and 2019, southwest monsoon made an onset over Kerala on June 8. The IMD had earlier forecast that monsoon would make an onset over Kerala around May 31. Skymet, a private weather forecasting station, said southwest monsoon made an onset over Kerala on May 30. However, the IMD said conditions were not ripe for declaring the onset of monsoon.

According to IMD, three parameters need to fulfilled for declaring the onset of the southwest monsoon over Kerala - If after May 10, 60 per cent of the 14 stations including Minicoy, Amini, Thiruvananthapuram, Punalur, Kollam, Allapuzha, Kottayam, Kochi, Thrissur, Kozhikode, Thalassery, Kannur, Kudulu and Mangalore report rainfall of 2.5 millimetres or more for two consecutive days, the onset over Kerala can be declared on the second day, provided other two criteria are also in concurrence. This has to be supplemented by the wind speed.

The depth of westerlies should be maintained up to 600 hectopascal (hPa), in the box equator to Latitude 10-degrees north and Longitude 55 degrees to 80-degrees east.