CHENNAI: The northeast monsoon will make its onset in the third week of October, and Tamil Nadu, especially the northern parts including Chennai, is likely to receive above-normal rains.
S Balachandran, Additional Director General of Meteorology at Regional Meteorological Centre, said as per the Long Range Forecast, north Tamil Nadu will receive above normal rain and southern districts will receive normal to below normal rain during the monsoon.
The state and other parts of south peninsular India are expected to receive above-normal rain, which is defined as more than 112% of the Long Period Average (LPA) during this period. The northeast monsoon is vital for Tamil Nadu as it receives nearly 48% of its annual rainfall during this season, playing a critical role in replenishing water reservoirs, supporting agriculture, and addressing the drinking water needs.
Balachandran said global climatic factors such as the El Niño-Southern Oscillation (ENSO) and Indian Ocean Dipole (IOD) will play a role in the monsoon dynamics. Currently, neutral ENSO conditions are being observed in the Pacific ocean, with a higher chance of La Niña developing during the post-monsoon season.
This is favourable for the northeast monsoon in Tamil Nadu. Similarly, above-average sea surface temperatures are noted across the Indian Ocean, with neutral IOD conditions expected to continue.
Tamil Nadu, Pondicherry, Andhra Pradesh, Rayalaseema, Kerala, Mahe and south interior Karnataka are expected to benefit from this increased rainfall.
The IMD has also highlighted potential temperature trends for October. Above-normal maximum temperatures are likely over most parts of the country, except in central India and the southern peninsula, where normal to below-normal temperatures are expected. Above-normal minimum temperatures are predicted for most regions, including Tamil Nadu, which could lead to warmer nights.
For the next five days, several districts in Tamil Nadu are likely to receive heavy rain due to a cyclonic circulation over the Comorin area that runs from north interior Karnataka across interior Tamil Nadu.
On Wednesday, ghat areas of Coimbatore, Nilgiris, Erode, Krishnagiri, Dharmapuri, Salem and Tirupattur will receive heavy rain and the following day, Ramanathapuram, Sivagangai, Pudukottai, Thanjavur, Nagapattinam, Mayiladuthurai, Cuddalore, Theni, Dindigul, Kallakurichi, Vellore, Ranipet, Tiruvannamalai and Tiruchy will join the party.