'Above' normal rainfall in Oct-Dec; several parts of central, southern peninsular India to be affected: IMD

The India Meteorological Department (IMD) on Tuesday predicted above normal rainfall in several parts of central, southern peninsular and northeast India from October to December. The IMD also predicted above-normal maximum temperatures in most parts of the country in October, with the exception of a few locations in central India and the bordering southern peninsula.

During a virtual press conference, IMD Director General Mrutyunjay Mohapatra stated that above-average rainfall is expected over the southern peninsula during the post-monsoon (northeast monsoon) season from October to December.

Mohapatra said that five meteorological subdivisions -- Tamil Nadu, coastal Andhra Pradesh, Rayalaseema, Kerala, and south interior Karnataka -- will be affected.

Rayalaseema, Yanam, coastal Andhra Pradesh, Puducherry, Tamil Nadu, Kerala, and south interior Karnataka experience the winter monsoon, often known as the latter quarter of the calendar year.

For Tamil Nadu, this is the principal rainfall season, wherein the state’s significant rainfall of the year is observed. 

However, with looming La Nina conditions in the equatorial Pacific Ocean, Tamil Nadu and Puducherry may get below-average rainfall this season. La Nina is known for suppressing the northeast monsoon over India. "During La Nina years, Tamil Nadu and Puducherry receive below-normal rainfall," the IMD head stated. However, with the Indian Ocean Dipole, the Pacific Ocean equivalent to the El Nino Southern Oscillation, expected to stay neutral in the coming weeks, the northeast monsoon's performance would be mostly determined by intra-seasonal events, according to IMD officials. The IMD predicts that the region could receive more than 112% of the long-term average of 334.13 mm of rainfall. Above normal rainfall is also expected in numerous portions of central India and certain sections of northeast India. However, the majority of northwest India, certain northeastern regions, and the country's south are predicted to receive normal to below-average rainfall, according to the report. 

The weather authority forecast that the country would get more than 115% of the long-period average of 75.4 mm of rainfall in October.

"The spatial distribution implies that several sections of the country received above-normal rainfall in October. However, some portions of northeast and northwest India, as well as a few pockets in the southern peninsula, are expected to get normal to below-average rainfall, according to the IMD. 

The southwest monsoon withdrawal is expected to accelerate in the next days, with rainfall ceasing in northwest and northern India. The IMD's extended range projection indicated that the northeast monsoon could arrive on schedule this year. The normal onset date is around October 15, with a standard deviation of four days.

The IMD forecasts that October will continue to be a rainy month across the country. The all-India rainfall for this month is expected to be 115% of the Long Period Average of 75.4mm. The majority of central and peninsular India, Uttar Pradesh, and surrounding areas will get "above" normal rainfall. October may be dry in Jammu & Kashmir and the eastern India region.

Day and night temperatures are expected to climb in the northeast area, including Jammu & Kashmir, West Bengal, Odisha, Gujarat, and Rajasthan, Punjab.