Yesterday was the third straight day Chennai city saw temperatures cross 40°C, like day before both City & Airport observatories recorded beyond 40°C with city recording 40.7°C the highest of this month and Airport recording 40.3°C the highest of the month.
In what possibly could be the last severe day of the heat wave conditions currently prevailing over North Coastal Tamil Nadu & South Andhra Pradesh the temperatures are expected to stay in the region of 40°C at a few places over Coastal Tamil Nadu especially the stretch between Chennai & Pondicherry. Like Yesterday when both the Chennai stations, Pondy & Cuddalore recorded above 40°C temperatures today also could see all these stations record similar temperatures.
There is some possibility of thunderstorms over a few places of North Tamil Nadu, considering the current heat wave conditions we would wait and watch on this development.
In Southwest #Monsoon2015 news it has been a very quite few days on the monsoon front with the monsoon axis firmly attached to the foothills of Himalaya with the only rains happening along the Himalayan Hills and adjoining plains. While the current Upper Air Cyclone Circulation over East India is expected to become a Monsoon low by some models, with a very active West Pacific, we will have to wait and watch if it actually materializes. In the meanwhile the forecast for the next two weeks also does not look good with most parts of India facing a negative anomaly. Considering how critical July is the next week or so could make or break this monsoon. 
Chennai Weather Update: #Chennai is expected to see another day of 40°C day time temperature though there is some possibility it may not be as high as yesterday so the century old record of warmest July day might still survive for one more year. Sea Breeze is expected to set in around 2 PM and is forecasted to be fairly strong and could move in onshore fairly deep making it a comfortable evening.