Environment

Private forecaster Skymet predicts ‘below normal’ Monsoon

Image for representational purpose only.   | Photo Credit: S. Rambabu

A month after ruling out a drought, private weather forecaster Skymet said it expects the coming monsoon rains to be “below normal” and about 7% short of the 89 cm the country usually gets from June to September. Not only is the monsoon expected to begin sluggishly but rain in July — a key month for agriculture — is expected to be nearly 9% short, the company said at a press briefing on Wednesday.

“In terms of geographical risk, Skymet expects that eastern India, along with a major portion of Central India, is likely to be at a higher risk of being rain deficient, especially during the first half of the season. The onset month of June is going to have a very sluggish start and deficit rains are likely to spill into July,” the company said in a statement. “The second half of the season would see better rainfall wherein August is expected to be a shade better than September.”

There is a 15% chance of a drought (seasonal rainfall less than 90% of the average), 30% chance of normal (seasonal rainfall that is between 96%-104% of the long period average or LPA), and 55% chance of below normal (seasonal rainfall that is between 90%-95% of LPA).

June was likely to post only 77% of its historical average of 164mm, July 91% of its average, according to Skymet.

On a monthly scale, the precipitation is expected to be: June — 77% of its average of 164 mm; July — 91% of its average of 289 mm; August — 2% more than its average of 261 mm; and September — 99% of its 173mm average.

‘Key culprit’

The key culprit, according to Jatin Singh, Managing Director, Skymet, was the El Niño — the warming of the central Pacific Ocean that’s frequently associated with drying monsoon rains.

“The Pacific Ocean has become strongly warmer than average. The model projections call for 80% chance of El Niño during March-May, dropping to 60% for June to August,” he said. The consensus, as of March among global meteorologists, is that the El Niño would form from March to May and there was a “less than 50% chance” of a strong El Niño from June-August.

Normal rain

An El Niño is declared when three straight months register a 0.5-1 degree C rise in sea surface temperatures in the Central Pacific.

In February, Skymet had predicted normal rain on the back of projections that the El Niño was fading rapidly.

Private forecaster Skymet predicts ‘below normal’ Monsoon
 

“However, the scenario changed completely in February and presently, moderate El Niño conditions are prevailing over the Pacific Ocean. In fact, El Niño could be declared anytime now. By May-June-July, there is a 66% chance of El Niño,” said the statement.

Officials from the India Meteorological Department (IMD) refused to comment on Skymet’s forecast.

The agency, which is expected to announce its forecast on April 15, said on April 1 that it expects “weak El Niño conditions” (a heating of around 0.5 C) to prevail during May-June.

“Any forecast of El Niño beyond that is premature,” an official told The Hindu.

The IMD was still factoring in sea surface temperature data in their forecast models and, with the Model Code of Conduct in effect for the Lok Sabha elections, required certain clearances before publicising the forecast, the official added.

Favourable parameter

Skymet said that another key parameter — the Indian Ocean Dipole, when the western Indian ocean is warmer and has more rain clouds than the east — appeared favourable to the Indian monsoon.

In 2018, both Skymet and the IMD over-estimated monsoon rainfall in April, and India ended up with below normal rainfall of 91% of what it typically gets in a normal monsoon year.

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Printable version | Jan 22, 2021 3:39:32 PM | https://www.thehindu.com/sci-tech/energy-and-environment/private-forecaster-skymet-predicts-below-normal-monsoon/article26720758.ece

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