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...
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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.