The Hindu Business Line : Dipole event prompts monsoon outlook upgrade

Thiruvananthapuram, June 30 India Meteorological Department (IMD) has upgraded projections about this year’s monsoon to be 100 per cent of the long-period average (LPA) with a model error of plus or minus 4 per cent.

This would go to make it a ‘normal’ monsoon year and is an improvement on the first long-range forecast made in April that quantified the season to be 99-per cent of LPA or ‘near-normal’.

Releasing its long-term forecast update on Monday, the IMD observed that factors such as sea surface temperatures over the Indian Ocean (resulting in Indian Ocean Dipole, or IOD events) also influence Indian monsoon rainfall in addition to the El Nino or La Nina in the equatorial Pacific.

IOD FACTORED IN

A few climate models suggest the possibility of development of a positive IOD, which is said to favour good performance of Indian monsoon, especially during September. Equatorial Pacific conditions and the possible evolution of IOD structure are being closely monitored.

In sector-wise forecasts, the IMD expected the monsoon to be 96 per cent of LPA for Northwest India, 101 per cent each in the North-East and Central India, and 98 per cent over the south peninsula, all with a model error of plus or minus 8 per cent.

Separately, it came out with a forecast for the crucial month of July which put the expected realisation around 98 per cent for the country as a whole with a model error of plus or minus 9 per cent. The accumulated seasonal rainfall over the country as a whole during the period June 1-29 is 121 per cent of the LPA.

BREAK MONSOON?

The IMD has predicted a decrease in rainfall activity over the west coast and central India from July 3 to 5 and a corresponding scale-up in rainfall activity over the Himalayan foothills. Subdued rainfall activity is likely to continue over interior south peninsula.

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