Rainfall was also reported in several places in and around Chennai on Tuesday. | Photo Credit: B. VELANKANNI RAJ
A fresh system, which is expected to form over the Bay of Bengal on Wednesday (October 21, 2026), is likely to sustain intense rainfall across Tamil Nadu till October 26. Southern and delta districts are likely to have an edge over northern districts in terms of heavy downpours.
The Regional Meteorological Centre (RMC) has forecast that a low-pressure area is expected to form over southwest Bay of Bengal and adjoining Tamil Nadu coast on Wednesday. Rainfall that pounded north coastal areas a few days ago is likely to move towards south and interior districts. The RMC has issued orange alerts for a few southern districts, including Tirunelveli and Thoothukudi, as they may receive heavy to very heavy rainfall up to 20 cm on Wednesday and Thursday (October 22, 2026).
While fairly widespread rainfall of moderate intensity may cover most parts of the State till October 26, south and delta districts, including Nagapattinam, Theni, and Ramanathapuram, may receive intense rainfall on Wednesday. Many interior districts such as Madurai and Karur, which were experiencing sizzling temperatures until a few days ago, may also record heavy rainfall this week.
A vigorous Northeast monsoon has helped wipe out rainfall deficit this month, with the State recording a 12% surplus so far. Various places such as Virudhunagar, Thoothukudi, Coimbatore, and Cuddalore received light to moderate rain till 6 p.m. on Tuesday (October 20, 2026). Rainfall was also reported in several places in and around Chennai.
V.R. Durai, Head, Regional Weather Forecasting Centre, said the weather conditions were also being monitored for isolated extremely heavy rainfall in southern districts. While the Bay of Bengal was expected to churn out another low-pressure area around Friday (October 23, 2026), it might not have a significant rainfall impact over Tamil Nadu.
Meanwhile, the weather system over the Arabian sea would maintain its intensity as a well-marked low-pressure area and move towards the Somalia coast by Thursday. The prevailing strong El Niño conditions were among the factors contributing to warmer sea conditions and formation of back-to-back weather systems. However, none of the back-to-back weather systems are expected to intensify into a cyclone, Mr. Durai added.
The RMC has forecast that some areas of Chennai will get moderate rainfall with thunderstorms and lightning on Wednesday.
Published - October 20, 2026 11:45 pm IST