The IMD has forecast a normal to above normal northeast monsoon over most parts of Tamil Nadu.
| Photo Credit: R. RAVINDRAN
Some parts of Tamil Nadu are likely to experience wet weather till October 8, with northern and interior districts set to record intense rainfall till Sunday.
According to the Regional Meteorological Centre (RMC), Chennai, scattered light to moderate rainfall may cover up to 50% of the weather stations in the State and Puducherry. Isolated places in Chengalpattu, Kancheepuram, Tiruvannamalai, Villupuram, Kallakurichi, and Salem districts may receive heavy rainfall on Friday.
Chennai and other northern districts, such as Vellore and Ranipet, are likely to record intense rainfall on Saturday. Interior districts such as Madurai and Dindigul, which are experiencing scorching heat, have chances of heavy rainfall on Sunday.
The prevailing weather systems, including a deep depression over the Bay of Bengal leading to wind convergence, are likely to influence rainfall activity across the State. The RMC also forecast that the maximum temperature may remain two to three degrees Celsius above normal in isolated pockets till Sunday.
Chennai may register day temperature of 33-34 degrees Celsius on Friday, with one or two spells of moderate rain in some areas.
The India Meteorological Department (IMD) has forecast a normal to above normal northeast monsoon over most parts of Tamil Nadu and below normal in the extreme southern parts based on its multi-model ensemble system.
Meanwhile, a few long-range forecasts using different models have indicated the probability of deficit rainfall. A monsoon forecast based on the South Indian Ocean Convergence Zone model by a team of former meteorologists of the IMD, including Onkari Prasad, suggests that districts such as Tirunelveli, Tenkasi, and Kanniyakumari may register a rainfall deficit. Poor rainfall may be experienced in December. Similarly, the Tamil Nadu Agricultural University’s district-level monsoon forecast, points to slightly negative rainfall departures in various districts, including Dharmapuri and Krishnagiri.
On the other hand, the Columbia University’s International Research Institute (IRI) multi-model forecast indicates probability of above normal rainfall in most parts of Tamil Nadu, and the European Centre for Medium-Range Weather Forecasts’ seasonal forecast also suggests normal to above normal is likely in the State. Weather experts said global climate factors such as Southern Oscillation Index, Negative Indian Ocean Dipole, and the likely development of La Nina conditions typically do not favour a good northeast monsoon.
However, Y.E.A. Raj, former Deputy Director-General of Meteorology, said the State had recorded normal and excess northeast monsoon during La Nina years in the past. Global weather parameters cannot always be directly correlated with monsoon performance due to its volatile nature, he added.
Published – October 02, 2025 08:25 pm IST
