Heavy rain till October 3: IMD sounds yellow alert across Tamil Nadu, Chennai braces for more

The India Meteorological Department has sounded a yellow alert across large parts of Tamil Nadu, warning of heavy rain with thunder and lightning till October 3, as an atmospheric circulation over the north coastal region and a trough running from interior Karnataka to the Gulf of Mannar feed moisture into the state. Heavy rain accompanied by thunder, lightning and gusty winds touching 50 km/h is likely in the Nilgiris, Coimbatore and Erode districts on Thursday, the weather office said. A yellow alert — the second rung of the IMD's four-colour warning scale — is in force for around forty districts, including Chennai, Chengalpattu, Cuddalore, Dharmapuri, Dindigul, Kanchipuram, Kanniyakumari, Karur, Krishnagiri, Madurai, Mayiladuthurai, Nagapattinam, Namakkal, Perambalur, Pudukkottai, Ramanathapuram, Ranipet, Salem, Sivaganga, Tenkasi, Thanjavur, Theni, Thiruvallur, Thiruvarur, Thoothukudi, Tiruchirappalli, Tirunelveli, Tirupattur, Tiruppur, Tiruvannamalai, Vellore, Viluppuram and Virudhunagar. The rest of Tamil Nadu, along with Puducherry and Karaikal, is expected to see light rain with thunder and lightning. In Chennai, where heavy showers have already triggered traffic snarls and waterlogging in low-lying areas, residents have been advised to stay alert. The weather office said an atmospheric circulation persists over the north coastal districts up to about 1.5 km above sea level, while a trough stretches from the south interior of Karnataka to the Gulf of Mannar at about 0.9 km — a combination that will keep the showers coming through the week. The downpour arrives as the state rides out the fag end of the southwest monsoon and looks ahead to the northeast monsoon, which accounts for the bulk of Tamil Nadu's annual rainfall. Officials have urged people in vulnerable and low-lying areas to remain cautious, and fishermen and coastal communities to stay alert for squally weather.