The heavy spells are right now spread from Madurantakkam to Pulicat Lake. IMD has upgraded the system from Well Marked Low Pressure Area to Depression
http://rsmcnewdelhi.imd.gov.in/images/bulletin/rsmc.pdf . This is expected to intensify into Deep Depression and move towards the Chennai Coast as per Numerical Models.
This break is temporary as more rains will start in the City soon and again there will be break. This Depression is going to linger off Chennai Coast for a while.
Courtesy : Tamil Nadu Weatherman FB page