Corroborating the assessment of a global forum of weather experts, the India Meteorological Department on Thursday predicted “below normal” rainfall during the upcoming monsoon season, with a rainfall of 95 per cent of the long period average [LPA]. The prediction comes with a margin of a plus or minus five per cent error.

In a statement, the Department said models indicated that there was a 33 per cent possibility of the rainfall being between 90 and 96 per cent of LPA and 35 per cent that it will be between 96 and 104 per cent of the LPA during the four month season from June to September.

Earlier on Wednesday, a forum of meteorologists under the aegis of the World Meteorological Organisation had also predicted a weak monsoon over most parts of the country. But, the experts had refrained from predicting upto what extent the rainfall would be below normal. Called the South Asian Climate Outlook Forum, the panel had looked at the possible scenario for the entire south Asia region.

The below par outlook for the monsoon this year comes in wake of the forecast of the possibility of evolution of the El Nino conditions in the equatorial pacific region. Latest forecasts from a majority of the global models that focus exclusively on the possibilities for the evolution of the El Nino or its counterpart La Nina have indicated that there was a 60 per cent probability for the development of El Nino during the monsoon season this year.

While El Nino condition has an adverse impact on the Indian monsoon, La Nina has a favourable impact. El Nino occurs when the waters in the equatorial pacific region become warmer than normal and La Nina when they become cooler than normal. At present, the temperatures of the waters are near normal, but there are indications they could warm up down the line.

Speaking to The Hindu, Director General of IMD, L.S. Rathore, said a redeeming feature was that the phenomenon called Indian Ocean Dipole, which also has some influence on the monsoon, is likely to be favourable this year and thus neutralise the possible adverse effects of El Nino to some extent. “We would keep a close watch on both El Nino and IOD.”