IMD vs Skymet: Fight heats up over who gets the forecast right

  • Zia Haq, Hindustan Times, New Delhi
  • Updated: Jul 03, 2015 12:04 IST

Sitting on a charpoy in his farm on a dry riverbed in the heart of Delhi, Ramesh Singh smiles as he looks at his field, shining green. The rains have been 16% surplus in June despite the official outlook of a “deficient” monsoon.

Government predictions going wrong barely raise eyebrows. This year, however, the forecast must spare the India meteorological department the blushes.

For the first time in its 140-year-old history, the IMD, or Met department, has serious competition. Skymet Weather Services Pvt Ltd, the country’s lone private forecaster, has virtually challenged the Met’s prediction of patchy rains with that of a normal monsoon.

The IMD forecast for July, which accounts for over a third of the season’s rain, too, differs widely from Skymet’s. While the Met sees a “considerable dip” in rains, Skymet talks of a rainy July.

The Met has forecast a deficient monsoon -- 88% of the average of 89 centimeters. The monsoon is considered normal if it is within 94-106% range.

Skymet’s monsoon forecasts, since it began projecting in 2012, have been largely similar to the Met’s but slightly more accurate. This has caught much attention, given that the monsoon is critical for Asia’s third-largest economy. In 2104, both failed to predict a drought.

This year, a growing El Nino, a weather pattern marked by higher sea temperatures known to choke the monsoon, is a major reason for Met’s ‘deficient’ forecast. Both Skymet and the IMD see a 90% probability of a drought due to this, but differ on the conclusions.

“I think the Met has put too much weight on the El Nino,” says Mahesh Palawat, chief meteorologist at Skymet and a former Indian Air Force weatherman.

In technology and manpower, Skymet, which has secured $4.5 million (about R28 cr) in funding from British investors, is no match to the publicly funded IMD.

The Met has been able to correctly predict the rainfall category -- such as normal or below normal -- at least 50% of the time in the past decade. The accuracy levels go up for a longer period.

Skymet has been predicting the monsoon for about four years, too small a period, some analysts say, to test its long-term accuracy.

Some glaring misses by the Met, however, have led to frustrations. For instance, in 2009 when it predicted normal rains, India saw its worst drought in 30 years.

Skymet believes a range of mitigating factors will keep monsoon normal. One, is the Indian Ocean Dipole, or IOD, which is the difference in sea-surface temperature between two spots in the ocean. If the IOD stays “positive or a neutral”, the monsoon overcomes the El Nino.

“The IOD is currently neutral and is on track to becoming positive in August. This is favourable,” says Skymet’s CEO Jatin Singh.

The forecaster points to another oceanic weather pattern -- the Madden–Julian oscillation that brings rain along its path. It moved over the Indian Ocean in June, bringing good rains, and is expected back this month.

The Met says it is convinced about poor rains in July and August. “No model globally is 100% accurate. Our model has been consistently improved and we are confident about our forecast,” says Shailesh Nayak, secretary, earth sciences department. The confidence stems from both the standard forecasting model and a new one being tested in collaboration with the US pointing to poor rains.

For now, the jury is still out.

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