Bountiful pre-monsoon rain season ahead for South Peninsula

Parts of the South Peninsula covering Kerala, coastal Karnataka-Goa and Rayalaseema may witness a bountiful pre-monsoon period (March-April-May) and a reasonably good first monsoon month of June, while July and August may turn drier. The rains may help prevent summer temperatures from peaking appreciably beyond their normal.

Tamil Nadu, too, is expected to run into a dry August, according to an updated six-month-outlook issued by the APEC Climate Centre at Busan in South Korea, in what it sees as an otherwise normal rainy season covering three of the four monsoon months (June to September).

La Nina to give into ‘neutral’ phase

The country as a whole may experience above normal rain through March to July, except the northern half (below normal in March) and Jammu, Kashmir, Ladakh, Himachal Pradesh and Uttarakhand (variously below normal until July).

The South Korean agency predicts around 59 per cent chance of weak La Nina conditions in the Equatorial and East Pacific during March-May, before it breaks down gradually to ‘neutral’ (neither La Nina or alter ego El Nino) conditions. The ‘neutral’ phase is expected to become dominant (~56 per cent) during June-August.

Importantly, the forecaster sees normal or slightly below normal temperatures for both India and the Indo-Chinese Peninsula (Cambodia, Laos, Myanmar, Thailand and Vietnam) during the six months under reference (March to August).

Skymet sees ‘normal’ monsoon

The South Korean forecast comes on the heels of India’s leading private forecaster Skymet Weather issuing a ‘normal’ (96-104 per cent of the long-period average) South-West monsoon (June-September) for the country this year. The India Meteorological Department (IMD) is expected to come out with its keenly awaited first-stage outlook later in April.

The last two monsoon seasons have been driven by back-to-back La Nina events, which have started shrinking now, Skymet Weather observed in its ‘preliminary monsoon forecast guidance for 2022 issued on Monday.’ It also means that monsoon 2022 is going to be a ‘devolving La Nina’ to start with, and turn ‘neutral’ later.

‘Corrupt’ monsoon ruled out

The Pacific conditions may not lead to above-normal or excess rainfall, but chances of a ‘corrupt’ monsoon are also ruled out. This could be one of the ‘normal’ monsoon years, making a robust start and finishing around the midway mark of the normal range, 96-104 per cent of the LPA (88 cm).

GP Sharma, President–Meteorology and Climate Change, Skymet Weather, said the predictability of Pacific conditions traditionally decreases during the ‘spring barrier’ period when weather models have a harder time making accurate forecasts.

Surplus run continues

Meanwhile, the country as a whole has maintained a surplus rain record (50 per cent above normal from January 1 to February 23) so far this winter, despite recent big deficits in Karnataka, Marathawada and Madhya Maharashtra, and lesser so in Gujarat, Kerala and Lakshadweep.

The US National Centres for Environmental Prediction, however, sees a fresh wave of rainfall across the Bay of Bengal entering the Tamil Nadu coast from March 3 and spreading out over Kerala and Karnataka as well as over Telangana, South coastal Andhra Pradesh and Lakshadweep. This could likely end the ongoing lean patch in the region.

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