It's just a low pressure system, lying south-east of Srilanka.
I still have lots of IF's and BUT's about the system because it's very slow to develop and move.
Here is the latest satellite imagery...
In Chennai, today morning it was cloudy and almost rain. Though the cloud was not heavy by no means but it was surely shower bearing ones. By mid-noon everything cleared off and it was just hazy towards the evening.
Temperature was Hi: 29.5°C @ 1:31pm
and Humidity was Low: 56% @ 1:37pm... very low indeed at noon.