Last evening saw many parts of Chennai record heavy spells of rains in particular areas in South Chennai got the heaviest spell of rains. Most places like Chennai Airport, Pozhichalur, Kolapakkam recorded about 30 mm rains in an hour spell as the thunderstorms moved from NW to SE giving rains further to parts like Adyar, OMR & ECR etc. Later in the evening parts of North Chennai like Red Hills etc got decent spell of rains while around midnight places further to the south of Chennai around Tambaram & beyond recorded good spell of rains. 
A look at the preliminary rainfall list for Tamil Nadu shows how the rains were pretty much skewed to the North Coastal Tamil Nadu region, in particular the places in and around Chennai. Chennai, Kanchipuram & Tiruvallur districts dominating the list with Namakkal, Melur & Devala the only places from elsewhere to record at least 1 cm rainfall in the AWS Network of IMD.
Today models are indicating a slightly poor day on the sea breeze possibility in the coastal areas beyond Pondicherry which could possibly impact the thunderstorm prospects for the places around Chennai. The stretch between Ramanathapuram & Nagappattinam is best placed to record some moderate rainfall today. It would not surprise to see if one or two places in Pudukottai / Sivaganga district record heavy spells of rains. Going by model estimates the rainfall prospects are better for places south of Chennai with a few places in the interior Tamil Nadu also see isolated heavy spells.
Prospects for Chennai look lesser compared to the last few days though things could change if sea breeze pattern changes during the course of the day.