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La Nina 'least likely' this year, says Australian Met

VINSON KURIAN THIRUVANANTHAPURAM | Updated on January 27, 2018 Published on January 31, 2017

After the Application Laboratory of the Japanese national forecaster Jamstec, the Australian Bureau of Meteorology too has hinted that the Equatorial Pacific will stay 'neutral' during the summer of 2017.

This means that no full-fledged El Nino or La Nina conditions are expected in this stretch of Pacific waters that could exert their respective beneficial or adverse impact on the Indian monsoon this year.

"A La Nina is the least likely scenario in...2017," the Australian Met said in its latest update, though forecasts made during this time of the year 'tend to be of lower accuracy.'

TILTING OF SCALES

While warming (El Nino) of the Equatorial East Pacific waters has, though with notable exceptions, been associated with a poor monsoon, their cooling (La Nina) has helped the latter's cause.

What can tilt the scales even in the face of an El Nino/La Nina is its near-shore cousin, the Indian Ocean Dipole (IOD), a product of a comparable warming anomaly in the Indian Ocean.

A positive IOD (warming of the western Indian Ocean) has been found to boost the Indian monsoon while a negative IOD (warming of East Indian Ocean) can harm it, as was evidenced as late as last year.

In 2016, the June-September season barely managed a near-normal rainfall over North India against forecasts of a surplus monsoon even as most of South India wilted from persistent dry conditions.

STRONGEST ON RECORD

The negative IOD phase values were among the strongest recorded in the last 50 years, which went on to scupper the October-December season (North-East monsoon) as well.

However, for the 2017 season, the Japanese forecaster sees a positive IOD panning out during the summer season, apparently a good augury for the Indian monsoon.

The Australian Bureau of Meteorology, whose IOD outlook is as keenly watched as of the Japanese, has not yet come out with its reading of the situation yet.

Meanwhile, a number of long-range forecasts made into the impending summer has hinted at a normal build-up for the Indian monsoon with a pre-monsoon that can 'deliver a surprise on the upside.'

Published on January 31, 2017
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