India Meteorological Department (IMD) announced on Thursday that the 2022 North-East monsoon has ceased sans pomp and show over Kerala-Mahe, South Interior Karnataka, Tamil Nadu-Puducherry-Karaikal, Rayalaseema and adjoining areas of Coastal Andhra Pradesh and Yanam. January has started off with a generally dry weather pattern over the entire region.
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What attracted weather watchers’ attention instead was news breaking out from a forecasting agency in Japan. The Application Laboratory of the Japanese national forecaster Jamstec has hinted the likely rollout of an El Niño in the far-away East Equatorial Pacific will be matched only by the emergence of a positive phase of the Indian Ocean Dipole (IOD) in India’s backyard.
Replay of 2019, 1997
This is loaded with implications, if it were to pan out as the Japanese agency sees it. An El Niño accompanied by a positive phase of the IOD promises to wash out worries of a deficient monsoon for India, though the threat from intense rains is something which it may have to contend with. None would need to look beyond years 2019 and 1997, two exceptional years of monsoon fury despite an El Niño, for guidance.
On Thursday, the Japanese agency said that an extended La Niña-like state, exact opposite to El Niño that underwrote four successful monsoons for India, continues in the Pacific. The SINTEX-F ensemble mean predicts that the La Niña-like state will gradually decay and an El Niño will occur in the summer. But the model goes on to predict positive IOD, despite a seasonally large uncertainty factor that limits forecast accuracy.
Large uncertainty factor
The positive IOD event in 2019 was among the strongest on record even as the monsoon wilted in the first month of June under an El Niño effect. Tables were turned into August and a very wet September. Research showed that the extremely positive IOD was conducive to a wetter-than-normal monsoon, especially late in the season when the IOD strengthened.
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Similarly, year 1997 was characterised by the rapid development of an El Niño whose strength had exceeded any previously observed this century. The basic understanding of the influence of El Niño on the monsoon suggested that it would end up substantially deficient. But a concurrent positive IOD in the neighbourhood ensured the contrary, and the monsoon turned out above normal by two percent.
Too early to judge
It may be too early to deduce a similar performance from the monsoon this year, but the outlook from the Japanese agency carries weight since its researchers discovered the IOD phenomena (positive and negative phases with contrasting influence on the Indian monsoon). It needs to be seen how many global agencies buy into these early projections of a positive IOD phase this year.
Cooler summer?
In near-term projections, the Japanese agency said February to April may see cooler weather for India along with parts of Indochina, the Philippines, Alaska, West Canada and adjoining West US, and the northern part of the South American continent. The rest of the globe may experience warmer-than-normal conditions.
As regards the seasonally averaged rainfall, a drier-than-normal condition is predicted for southern parts of the US, Mexico, La Plata, some parts of Australia, Mozambique, West Africa, Indonesia, and South-East China. In contrast, West Canada, northern half of the South American Continent, Central Australia, southern Africa, Madagascar, Mauritius, parts of Europe and Russia, Nepal, Bhutan, Central China and the Philippines may see wetter-than-normal conditions.