26.4.14

A below normal monsoon predicted


Acknowledging the shadow of El Nino on this year’s monsoon, the India Meteorological Department (IMD) has predicted below normal June-September rains at 95% of the long period average.
In its first long period forecast for this year, IMD said there was a 56% probability of below normal to deficient rains, as compared to a 44% chance of rains being normal or better. The department said there was a 60% chance of an El Nino — a periodic warming of sea temperatures in some parts of equatorial Pacific that often dampens the critically important summer monsoon in India.
The predictions have an error margin of 5%. The department will release a more detailed update on the monsoon in June.
While predicting below-normal monsoon this year, IMD also released forecasts of two experimental models, one of which predicts deficient rains at 88% of normal. IMD director general L S Rathore said, however, it was too early to know for sure whether the monsoon should be a cause for worry.
“We are going by the operational forecast which is showing 95%. However, there are several models that are being referred to and we have issued forecasts by two such models. The monsoon mission model is predicting 96% of the long period average while the ESSO IMD seasonal forecast is showing 88% of the LPA,” Rathore said. The second model was very close in its assessment last year, he said but added that “these are only experimental models and we cannot use their data with any kind of certainty.”
IMD has been periodically updating its methodology for the complex task of predicting the monsoon. The department, however, continues to battle the impression that its accuracy drops markedly when rains fail
In keeping with the latest updates from international agencies, IMD said that chances of an El Nino occurring this summer were high. “Latest forecast from a majority of the models indicate a warming trend in sea surface temperatures over the equatorial Pacific reaching to El Nino level during the southwest monsoon season, with a probability of around 60%,” the IMD release said.
The release also said that there was little chance, as of now, of conditions in the Indian Ocean turning favourable to the monsoon and countering the effect of the El Nino.


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