The monsoon is likely to hit Kerala on June 4, three days later than the normal onset date, with an error margin of plus/minus two days, private weather forecaster Skymet said here on Tuesday.

Skymet, which has also come out with region-wise forecasts, expects the progress of the monsoon to be sluggish. “All the four regions are going to witness lesser-than-normal rainfall this season. East and North-East India and the Central parts will be poorer than North-West India and the South Peninsula,” Skymet MD Jatin Singh told mediapersons here on Tuesday. On April 3, Skymet had predicted below-normal rains of 93 per cent of the long period average (LPA).


GP Sharma, President (Meteorology & Climate Change) at Skymet, said there will be some El Nino impact. El Nino refers to the warming of the Central/Eastern equatorial Pacific Ocean, which generally suppresses monsoon rainfall.

The forecast sees the monsoon arriving at the Andaman and Nicobar Islands on May 22. The onset in Kerala will coincide with the onset in some parts of North-East India. This will be preceded by intense pre-monsoon rains in Kerala. Considering the intensity, it might be difficult to distinguish between pre-monsoon and monsoon showers, said Sharma.

From June through September, Skymet said, there will be zero per cent chance of excess (seasonal rainfall that is more than 110 per cent of LPA) or above-normal rainfall (105-110 per cent of LPA). There is a 30 per cent chance of normal rainfall (96-104 per cent of LPA), 55 per cent chance of below-normal rainfall (90-95 per cent of LPA) and 15 per cent chance of drought (less than 90 per cent of LPA), it added.

The private forecaster made it clear that it does not coordinate with the government-run India Meteorological Department (IMD). There have been differences in forecasts by these two agencies. While Skymet has predicted a below-normal monsoon this year, the IMD has said it is likely to be near-normal, which could be 96 per cent of the LPA, with an error margin of plus-minus 5 per cent.

The IMD also said weak El Nino conditions are likely to prevail during the monsoon season with reduced intensity in the latter part. It will come out with a second-stage monsoon forecast in the first week of June.