The Depression over Arabian Sea is now “Cyclone Ashobaa” and is currently moving towards Persian Gulf. Thanks to Cyclone Ashobaa the Southwest Monsoon has established itself over the west coast up to Goa.
Now that Cyclone Ashobaa has moved away from an influencing role the thunderstorm seasons would be back over Peninsular Inda. For South AP & adjoining parts of North Interior Tamil Nadu Rains are a possibility today. A few places around Vellore / Tirupati etc could see thunderstorms today.
The thunderstorms would be triggered by convection radiated from ground heat and aided possibly by the Fading UAC off the coast of AP which has detached itself from the influence of Cyclone Ashobaa
The rain prospects for Chennai would depend on Wind Pattern and the sustenance of the thunderstorms from the interior places, we will keep a close watch and update you once there is a firm prospect of rains for Chennai.