Light to moderate rain with Thunderstorm and Lightning is likely to occur at isolated places over Chengalpattu, Coimbatore, Dharmapuri, Erode, Karur, Krishnagiri, Namakkal, Perambalur, Salem, The Nilgiris, Tiruchirappalli, Tiruvannamalai, Viluppuram and Puducherry in next 3 hours.