Monsoon off to a late start

The June-September monsoon is unlikely to hit Kerala, its first port of call in the Indian mainland, on May 30, as forecast, but meteorologists say they do not expect the sluggish rains to be delayed by more than a couple of days.

Although the monsoon’s onset has no correlation with its progress during its four-month journey across India, it remains threatened by a strong El Niño taking hold across the Pacific Ocean, raising worries for the government and farmers.

The rains, vital for Asia’s third-largest economy, need to be robust for good farm output. This year, they are critical, as rural incomes fell 1.4% between January and March due to a series of weather shocks, fresh GDP figures showed.

The effects of El Niño, a weather glitch, can ripple across the world, from drier conditions in India to storms in Peru.

In developing countries, an El Niño can roil agricultural markets.

June 1 is considered the normal arrival date for the rains, but the India Meteorological Department forecast landfall on May 30, with a four-day margin of error. “It may not happen on May 30 but we don’t expect a delay beyond four days, which is quite normal,” said DS Pai, the Met’s lead monsoon forecaster.

So, how will the monsoon behave? The jury is still out. The rainy spell remains highly vulnerable. Eventually, it depends on the winner in a meteorological “tug of war” currently playing out in the seas.

Forecasters are closely watching a key Indian Ocean barometer -- called the Indian Ocean Dipole or IOD -- that can sometimes protect the monsoon from being destroyed by an El Niño.

The IOD is the difference in sea- surface temperature between two areas (or poles) in the Indian Ocean -- a western pole in the Arabian Sea and an eastern pole near Indonesia.

“The IOD is currently neutral,” Pai said. In this fight between the IOD and El Niño, a neutral or positive IOD aids the monsoon, while a negative IOD is bad news. Three of five global models favour values near positive IOD thresholds in the next four months, which is reason for hope for India and bad news for Australia.