The Regional Meteorological Centre (RMC), Chennai, has warned that a new low-pressure area is likely to form over the southwest Bay of Bengal within the next 24 hours, which could trigger widespread rainfall across Tamil Nadu.
In its bulletin, the weather office said an atmospheric circulation is prevailing over the southwest Bay of Bengal and adjoining Tamil Nadu coastal areas, and it may intensify into a low-pressure area today. The movement of the system will determine whether the northeast monsoon strengthens further in the coming days.
An orange alert has been issued for Thoothukudi, Tirunelveli and Kanniyakumari districts, where very heavy rain with thunder, lightning and strong winds is likely today.
Heavy rain with thunder and gusty winds is also expected in Nilgiris, Coimbatore, Erode, Tiruppur, Namakkal, Karur, Theni, Dindigul, Tenkasi, Madurai, Virudhunagar, Pudukkottai, Thanjavur, Tiruvarur, Nagapattinam, Mayiladuthurai, Sivaganga, Ramanathapuram and Karaikal. Chennai and its suburbs are likely to remain cloudy, with light rain and thunderstorms in a few places.
The RMC noted that rainfall has already been recorded in parts of the state, with 9 cm reported in Amaravathi Pudur and Perattukottai (Sivaganga) and Mangalakkudi (Ramanathapuram), followed by 8 cm in Thiruvadanai (Ramanathapuram), Thalainayar (Nagapattinam) and Vadapathimangalam (Tiruvarur). With the system expected to form today, heavy rain is forecast to continue over Tamil Nadu and Puducherry from October 21 to 25.
