Monsoon is here, says Skymet, but IMD differs

The monsoon has arrived in Kerala before its onset schedule, private agency Skymet Weather said on Saturday, but the India Meteorological Department said conditions were not yet ripe for the declaration. Skymet Weather CEO Jatin Singh said all conditions such as rainfall, Outwave Longwave Radiation value and wind speed had been met to declare the arrival of the southwest monsoon.

The southwest monsoon has arrived in Kerala before its onset schedule, private agency Skymet Weather said on Saturday, but India’s official forecaster IMD said conditions are not yet ripe for the declaration.

Skymet Weather CEO Jatin Singh said all conditions such as rainfall, Outwave Longwave Radiation (OLR) value and wind speed have been met to declare the arrival of the southwest monsoon over Kerala.

“All the onset conditions including rainfall, OLR value, wind speed, are met. Finally, the 4-month long festival begins,” the private forecaster tweeted.

The onset of monsoon over Kerala marks the commencement of four-month rainy season in the country.

Skymet had predicted that monsoon will hit Kerala on May 28 with an error margin of plus or minus 2 days. Whereas, the India Meteorological Department (IMD) had said the monsoon will make an onset over Kerala on June 5, four days after its normal onset date.

According to the IMD, there are three major conditions to declare the onset of monsoon.

The first is if, after May 10, 60 per cent of the 14 weather stations report rainfall of 2.5 millimetres or more for two consecutive days, the onset over Kerala will be declared on the second day. The second is the depth of westerlies should be maintained up to 600 hectopascals (hpa) and the third is the Outwave Longwave Radiation should be below 200 watt per square metre (wm-2).