While South Tamil Nadu was enjoying heavy & widespread rains over the last few days it was pretty much dry over North Tamil Nadu except for isolated Thunderstorms. Is it going to change? Will Chennai be lucky again?
Starting from Friday evening North Tamil Nadu especially interior places has a fair bit of rains. While we are not sure if it would be widespread we expect a few places to get heavy rainfall. Places around the Western Ghats could be among those to get heavy rains. 
A combination of a upper level trough dipping south and the presence of a marginal upper level circulation over Interior Tamil Nadu is creating an instable zone providing conducive environment for rains over a few places of Tamil Nadu.
The rain prospects for Chennai depend on how further eastward the rains move from Interior places towards the coast. It looks possible Chennai to could get some decent spells of rains from Friday, this spell of rains would continue through bursts until may be Sunday early morning.