Global climate models variously predict that it will be a toss-up between ‘neutral’ (neither El Nino or La Nina) and an El Nino in the tropical East Pacific by next summer (2023) that is followed by the South-West monsoon in India, even as a rare third La Nina on a trot prepares to run its course by the end of this year or early next.

A probabilistic outlook from the US triumvirate of Climate Prediction Centre-National Centres for Environmental Prediction-National Oceanic and Atmospheric Administration said the tropical Pacific atmospheric is consistent with a La Nina. Not surprisingly, sea-surface temperatures are below average across most of the Pacific Ocean.

‘Neutral,’ for the most part

The ongoing La Nina, which has been driving the fourth successful Indian monsoon, is favored to continue through the winter of 2022-23 (December-January and February), with a 91 per cent chance in September-November, decreasing to a 54 per cent in January-March 2023. Chances of the La Niña gradually decrease through the autumn (October-November-December) and winter, with ‘neutral’ conditions favored to resume during February-April 2023.

Japanese El Nino alert

The International Research Instiute for Climate and Society at Columbia University in the US gave an extended outlook suggesting up to 70 per cent chances for ‘neutral’ conditions during April-May-June of 2023 while those for La Nina and El Nino are likely to be at a low 15 per cent each. But the Application Laboratory of the Japanese national forecaster Jamstec went to the extent of saying an El Nino may set in during the March-April-May 2023 coinciding with pre-monsoon in India. These are all early forecasts that need to be correlated with the actual turn of events.

Good winter monsoon?

The Busan, South Korea-based APEC Climate Centre said that the probability for La Niña conditions is expected to be 77 per cent during October–December 2022 and gradually decrease to 33 per cent by January–March 2023. Its intensity is likely to be weak. Probability of an El Nino would be around 10 per cent by this time, slightly higher than those for a La Nina, while those for ‘neutral’ conditions are likely to be around 50 per cent during this period, till when extended forecasts are available.

Exceptional year likely

A La Nina has correlated negatively with the North-East monsoon (returning monsoon) for South India that runs from October to December, though with exceptions. According to early outlook from the APEC Climate Centre, this year (2022) could prove an exception since it has forecast enhanced probability for above normal precipitation for the Bay of Bengal and southern India, along with the eastern Indian Ocean and eastern Australia. The last two will also benefit from a concurrent negative Indian Ocean Dipole (an El Nino-La Nina twin in the Indian Ocean) in which the East Indian Ocean warms up relative to the West).

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