US says El Nino just weeks away, earlier than expected

El Nino’s shadow over this year’s monsoon in India may have just got longer. Latest forecasts from international agencies suggest El Nino could be just weeks away, setting in earlier than expected. It’s now likely that the weather condition will prevail during most of the four-month monsoon period as opposed to previous expectations that it’ll develop in the second half of the season.

In their update released late Thursday, US agencies under the National Ocean and Atmospheric Administration (NOAA) raised the odds of El Nino emerging in the May-July period to 82%, up from a 61% probability projected in their release last month. NOAA’s Climate Prediction Centre (CPC) indicated rapid heating in the Pacific Ocean, with the surface-water temperature in the relevant area of the Pacific recorded at 0.4 degree Celsius above normal in early May, close to the 0.5-degree threshold of El Nino setting in.

“If the El Nino forms earlier than expected, it is likely to have an impact on monsoon rainfall,” said IMD chief Mrutyunjay Mohapatra. In its first monsoon outlook for this year issued last month, IMD had accounted for the possibility of El Nino emerging around the second half of the season.

IMD’s forecast — below-normal monsoon at 92% of long period average — was the lowest projection of seasonal rainfall by the national forecaster since it switched to a new multi-model ensemble system in 2007. The agency will release its second monsoon outlook next week.

El Nino is a periodic episode of abnormal warming of surface waters in central and east equatorial Pacific with associated changes in wind-flow patterns that impact weather across the globe. It’s associated with depressed monsoon rainfall in India and around 70% of El Nino events since 1980 have corresponded with below normal or deficient monsoons, often leading to widespread drought.

European agency ECMWF had said earlier this month that El Nino may emerge in May itself. Most models indicate that it would possibly be among the strongest events on record, with major implications for weather across the globe.

The CPC release gave a two-thirds probability to El Nino strengthening into a strong event — with a 37% chance of it turning into a ‘super’ El Nino by Nov-Jan.