IMD & Skymet competing monsoon forecasts: Who will get it right?

NEW DELHI: Competing forecasts have injected a new dimension to the hazardous business of monsoon prediction this year, with private weather agency Skymet taking a completely different view of how rains would perform in what are the most crucial four months of the year for India's economy.
While the country's official agency, India Meteorological Department, has predicted a deficient monsoon with rains falling 12 per cent short of normal, the new kid on the block Skymet has stuck to its forecast of 'normal' rains at 102 per cent of the average.

Skymet has been making monsoon predictions for four years now. But never has its forecast been so different from IMD's. That, and the fact that rains in June appeared to have followed Skymet's script rather that IMD's, helped the agency grab media attention like never before.

However, the "contest" over whose prediction would be more accurate is far from over.

As on Monday, average countrywide rainfall in July was 30 per cent below normal. And with no signs of the monsoon strengthening in the next seven days, July's rain output could end up closer to IMD's prediction of 92 per cent rains for the month. Skymet had forecast July rains to be 104 per cent of average.

Overall, the monsoon is currently 3 per cent below normal. According to Skymet's forecast, the monsoon is likely to be 2 per cent above normal.

"Since July and August are crucial months, we are keeping our fingers crossed," said G P Sharma, Skymet's VP, meteorology. The agency believes the second half of July will see better rains. Sharma said Madden Julian Oscillation — the factor that led to good rains in June — could make a comeback in the second half of this month and activate the monsoon.

Sharma, however, said the agency could downgrade its prediction in the event of the monsoon not strengthening in the next week or so.

Irrespective of the final outcome, several officials and scientists in government meteorological institutes feel it is difficult for private weather agencies such as Skymet to acquire the infrastructure for accurate long-term weather forecasting.

"IMD is using a supercomputer for developing a coupled weather model for monsoon forecasts. We have been fine-tuning it for the past three years and it will be another two years before the model reaches its maximum possible accuracy. Very high computing power is required to achieve high accuracy," said M Rajeevan, director of Indian Institute of Tropical Meteorology, which is developing the computer model.

Skymet said it uses a CFS weather model for its forecasts. "We have doubled our computing capacity in the past six months," said Sharma, who was earlier in the meteorology department of the Indian Air Force.