After a couple of weeks of fairly comfortable weather in Chennai thanks to the drier outlook along with the Westerlies strengthening we are likely to see an increase in temperatures. Last night saw isolated places get moderate rains in Chennai which made it a comfortable evening even though sea breeze struggled to make any major headway against the Westerlies right through the evening.
Southwest Monsoon which was going through a lull phase since the advent of of second fortnight of July is expected to revive and possibly shift to top gear aided by a much needed Low Pressure in Bay of Bengal. While the second fortnight of July saw the interiors enjoy some of the heaviest spells of the season in the region the core monsoon areas were left in the lurch as the Northward shift of the Monsoon trough resulted in Monsoon Winds disturbed and unfavorable for the West Coast.
The last few days have seen Southwest Monsoon pick up pace slowly as Maharashtra started getting heavy rains at many places. Yesterday saw many place in the state record rains in excess of 20 cm while today Mahableshwar has recorded well over 20 cms by 5:30 in the morning. Things are expected to be similar today as well with a few places to the Northeast of Mumbai, around the Nashik / Igatpuri region, getting extremely heavy rainfalls possibly triggering heavy inflow into rivers like Godavari. The Sahyadri ghat region running along the West Coast also could see heavy to very heavy rains in a few places.
In the meanwhile Weather in Chennai is likely to be dominated by dry conditions & may be an increase in day time temperature to around 36 / 37°C with Westerlies dominating as one can observe from the wind chart expected for the day across Tamil Nadu. The Westerlies are going to be pretty much setting the tone for the day with sea breeze expected to play a very subdued role. Parts of North Tamil Nadu & Central Tamil Nadu are likely to see very gusty conditions with Westerly winds reaching almost 50 kms an hour in certain stretches. 
The combination of strong Westerlies and clearer skies is likely to influence the temperature pattern as well across Tamil Nadu. Temperatures are expected to notch up a couple of degrees over many places particularly interior places that is likely to see day time maximum temperature reach 38 / 39 degrees in a few places.