Yesterday saw one of the hottest days this August in Tamil Nadu as 9 places recorded more than 38 degrees as maximum temperature. Places in North Coastal Tamil Nadu like Chennai, Cuddalore, Puduchery, and slightly to the south along the coast Nagappattinam & Adirampattinam all recorded more than 3 degrees above normal temperatures. With Northwesterly surface winds blowing right through the day the temperatures have stayed well above normal across most parts of the state.
Things are expected to be similar today as well with many places in Tamil Nadu expected to see day time maximum temperature in the region of 38 degrees while it would not be surprise if one or two places in North Tamil Nadu inch closer to 40 degrees as Northwesterly winds increase the heat radiation along with a drop in humidity making it an uncomfortable day.
The saving grace is likely to be the sea breeze which is expected to set in early around late afternoon by 2 / 3 PM in Coastal Tamil Nadu. This would not only get to a decrease in temperature but is likely to trigger some isolated thunderstorms as well in the region particularly around the places within 100 kms from the coastline. The stretch between Chennai & Pondicherry looks ideal going by model estimates for these thunderstorms. Unfortunately the available moisture at upper levels are fairly low due to the NW winds. This would mean like yesterday the thunderstorms would be weak and probably isolated giving rains to a small area rather than be widespread. South Chennai suburbs possibly stand a better chance for rains compared to the rest of the city.
On a macro level the monsoon depression now lying over Central India is likely to bring heavy rains over parts of Madhya Pradesh, UP and Chhattisgarh as it moves in a westward direction. It is expected to weaken as it moves further west. In the meanwhile we are likely to see another low pressure form over North Bay in the next couple of days which is likely to keep the monsoon trough active.
West Coast is likely to see subdued rainfall activity with the exception of South Karnataka around Mangalore / Kodagu region & parts of North Kerala that could see moderate rainfall activity around Wayanad region.