Light to Moderate Rain with thunderstorm and lightning is likely to occur at isolated places over Chengalpattu, Chennai, Cuddalore, Dharmapuri, Erode, Kallakurichi, Kancheepuram, Krishnagiri, Namakkal, Perambalur, Salem, Tiruchirappalli, Tiruvannamalai, Viluppuram, Pondicherry in next 3 hours.