The cyclonic circulation over the Bay of Bengal persists at 0.9 km above the mean sea level off the Tamil Nadu coast. This will cause light to moderate shower with thunderstorms in the next 48 hours over coastal Tamil Nadu and Puducherry, said sources from the Regional Meteorological Centre.

“The sky condition in Chennai and the surrounding areas is likely to be generally cloudy. Thunderstorm with light to moderate rain is likely to occur in some areas. Maximum and minimum temperatures are likely to be around 34ºC and 25ºC respectively,” said N Puviarasan, director, RMC.

With areas in Coimbatore, Tiruppur, Erode and The Nilgiris receiving high rainfall over the night and in the early morning, districts like Madurai, Sivaganga, Coimbatore, The Nilgiris, Tiruppur, Theni, Dindigul, Pudukottai, Cuddalore, and Mayiladuthurai are expected to receive heavy rainfall and thunderstorms on Thursday.

This spells good news for Chennai’s water storage, said weather blogger Pradeep John, who runs the page Tamil Nadu Weatherman. “With Madden–Julian oscillation coming into Indian Basin, we are going into a very active phase of monsoon and might see most of the lakes filled up even well before the end of November. Good news as we might see some cleaning happening in our filthy rivers. With the core city getting good rain on October 22 and 29, the groundwater level should improve with more rain in November, the lakes are also expected to get adequate storage,” he said.