IMD retains normal monsoon forecast; deficient rains in June

NEW DELHI — Barring the northwestern region, India is set to receive normal rainfall this monsoon season despite the El Nino phenomenon which is set to return after a three-year hiatus, the weather office said on Friday.

However, most parts of the country will witness deficient showers in June, except some pockets in peninsular regions such as south Karnataka and northern Tamil Nadu, Rajasthan and Ladakh, the India Meteorological Department said in its update of the long range forecast for the season.

The weather office said the warming of the equatorial Pacific Ocean has begun and there was a 90 per cent probability of development of the El Nino phenomenon, which is known to affect monsoon rains in India.

However, a positive Indian Ocean Dipole is likely to develop during the monsoon season which would offset the adverse impact of the El Nino and bring rains to most parts of the country.

“It is El Nino and positive IOD this year. The impact of El Nino in central India was likely to be compensated by positive IOD. But that may not happen in the case of northwest India,” D Sivananda Pai, head of the IMD’s Environment Monitoring and Research Center told reporters here.

In view of the above, IMD has retained its forecast for a normal monsoon season for the country, barring the northwestern region, which includes Rajasthan. Haryana and Punjab, considered as the granaries of India.

The weather office said rainfall during the June-September period is likely to be 96 per cent of the long-term average, with an error margin of four per cent of the long period average.

The IMD also said that southwest monsoon over the ‘monsoon convergence zone’, or the rainfed-regions of India, is expected to be normal at 96-106 per cent of the LPA.

In April, the IMD had forecast a normal monsoon with the country expected to witness 96 per cent rains of the long-term average, with an error margin of five per cent of the long period average.

The weather office defines normal rainfall as between 96 per cent and 104 per cent of the 50-year average of 87 cm for the four-month southwest monsoon season.

Southwest monsoon normally sets in over Kerala on June 1 with a standard deviation of about seven days. IMD has been issuing operational forecasts for the date of monsoon onset over Kerala from 2005 onwards.

Last year, the monsoon reached Kerala on May 29. The operational forecasts of the date of monsoon onset over Kerala during the past 18 years (2005-2022) were proved to be correct except in 2015, the IMD said.