The Regional Meteorological Centre (RMC) in Chennai has placed seven Tamil Nadu districts — Pudukkottai, Thanjavur, Tiruvarur, Nagapattinam, Mayiladuthurai, Cuddalore and Villupuram — under a very heavy rainfall alert for Tuesday, October 20. Gusty winds reaching up to 50 kilometres per hour may accompany the intense spells in the worst-hit areas, the weather office said.

The RMC attributed the conditions to an upper-air cyclonic circulation over the southwest Bay of Bengal, off the north Tamil Nadu coast, with a trough extending from the circulation towards the northwest Bay of Bengal. The seven districts on the highest alert sit in the Cauvery delta belt and along the coast, areas vulnerable to intense rain during the northeast monsoon.

Heavy rain is also forecast across a much wider stretch of the state on Tuesday, including Tiruvallur, Kancheepuram, Chengalpattu, Tiruchirappalli, Ariyalur, Perambalur, Ranipet, Vellore and Tirupattur, and in the south in Theni, Dindigul, Madurai, Virudhunagar and Ramanathapuram. Puducherry and Karaikal are also covered by the day's warnings. For Chennai, the RMC has predicted heavy rain accompanied by thunderstorms and lightning at one or two places on Tuesday evening, with the intense spells expected to be localised.

On Wednesday, the focus of very heavy rainfall is expected to shift towards southern Tamil Nadu, with Theni, Tenkasi, Virudhunagar, Tirunelveli and Kanyakumari districts likely to receive very heavy showers. Residents in low-lying and coastal areas have been advised to follow district administration and IMD updates closely as the northeast monsoon remains active over the state.

Sources: Regional Meteorological Centre (IMD), Chennai; reported by BizzBuzz, Nation Press and Careerindia.