Southern Peninsular India Witnesses Sixth Driest October In Over A Century As IMD Reports Over 60 Per Cent Rainfall Deficit

The India Meteorological Department (IMD) on Tuesday (31 October) reported that the southern peninsula of India has seen its sixth driest October in over a century, with records going back 123 years.

The area, which includes Kerala, Mahe, the southern interior of Karnataka, Tamil Nadu, Karaikal, Puducherry, the coastal regions of Andhra Pradesh, Yanam, and Rayalaseema, recorded a scant 74.9mm of rainfall in October, marking a shortfall of over 60 per cent from the normal levels.

Typically, October brings rain to southern peninsular India from the departing southwest monsoon as well as the arriving northeast monsoon. However, this year witnessed an unusual dry spell of nearly 25 days in October, according to IMD officials.

In contrast to past few years, the southwest monsoon concluded almost punctually, following a season that lasted 134 days.

A key factor in the deficient rainfall was the northeast monsoon's arrival, which overlapped with various oceanic activities.

Although the northeast monsoon began on October 21, concurrent developments in the Bay of Bengal and the formation of cyclones impacted the commencement of the monsoon.

“This year, the commencement of the northeast monsoon coincided with the genesis of the cyclone Hamoon which crossed the Bangladesh coast. As a result, most of the moisture was dragged away from southern peninsular India. So much so that it even altered the wind flow pattern. Thus, it was a weak northeast monsoon onset,” explained Mrutyunjay Mohapatra, director general, IMD, Indian Express reported.

The IMD's data up to 31 October shows the following rainfall figures: coastal Andhra Pradesh and Yanam received 18mm (90 per cent below average), Rayalaseema got 12.7mm (also 90 per cent below average), Tamil Nadu along with Karaikal and Puducherry had 98.5mm (43 per cent below average), south interior Karnataka received 64.5mm (53 per cent below average), and Kerala recorded 311mm, which is just 1 per cent less than the normal mark.

With 2023 being an El Nino year, when combined with the positive phase of the Indian Ocean Dipole (IOD), such rainfall deficits are commonly observed during October and have been previously recorded, added Mohapatra.

It's noteworthy that 2023, along with 2016 and 1988, features among the six driest Octobers recorded in the southern peninsula, all of which were El Nino years.

“During El Nino years and the positive IOD phase, there is less rainfall over northern Tamil Nadu and adjoining areas. Whereas, the southernmost areas of Tamil Nadu and Kerala receive good rainfall in October,” he said.

Although the northeast monsoon began sluggishly, it has intensified over the last couple of days. The IMD predicts that this active phase will bring considerable rainfall across Kerala and Tamil Nadu in the coming week.

"A fresh rainfall spell will affect these states during November 3-5,” the IMD chief official said.

The rainfall outlook for November is also optimistic for this region. The historical Long Period Average of rainfall for south peninsular India in November, calculated from data between 1971 and 2020, stands at approximately 118.69 mm.

“The monthly rainfall during November over south peninsular India is most likely to be normal and range between 77 – 123 per cent of the Long Period Average, which is 118.69mm (1971-2020 record),” the IMD said in its forecast issued on Tuesday.