IMD: Oct-Dec rainfall to be above normal, after 108% in June-September

“The seasonal rainfall southeastern peninsular India will be 112 percent of the Long Period Average of 334.13mm over during October – December,” Mrutyunjay Mohapatra, director general, IMD, at the time of issuing the forecast for the post-monsoon season.

Also known as winter monsoon, rainfall during the last quarter of the calendar year is predominant over Rayalaseema, Yanam, coastal Andhra Pradesh, Puducherry, Tamil Nadu, Kerala and south interior Karnataka. For Tamil Nadu, this is the chief rainfall season, wherein the state’s major rainfall of the year is recorded.

However, with the impending La Nina conditions emerging along the equatorial Pacific Ocean, there could be below normal rainfall over Tamil Nadu and Puducherry during the upcoming season. La Nina is known to suppress the northeast monsoon over India.

“During La Nina years, Tamil Nadu and Puducherry receive below normal rainfall,” added the IMD chief.

However, with the Indian Ocean Dipole, which is the counterpart of the El Nino Southern Oscillation from the Pacific Ocean, likely to remain neutral during the upcoming weeks, the northeast monsoon’s performance will largely depend on the intra-seasonal developments, the IMD officials said.

The southwest monsoon withdrawal is likely to pick up pace during the next few days and rainfall cessation from over northwest and northern India is imminent. The extended range forecast issued by the IMD suggested that the northeast monsoon onset could be on time this year. The normal date for the onset is around October 15 with a standard deviation of about four days.

Over the country, October will continue to remain a rainy month, the IMD has forecast. The all-India rainfall during this month has been forecast to be 115 per cent of the Long Period Average of 75.4mm. ‘Above’ normal rainfall will lash a majority of the geographical regions spanning central and peninsular India, Uttar Pradesh and neighbourhood areas. October could be dry over Jammu and Kashmir and eastern India region.

Both day and night temperatures are set to soar over the northeast region, Jammu and Kashmir, West Bengal, Odisha, Gujarat and Rajasthan, Punjab.