According to Cyclone Warning Division of the IMD, satellite imagery indicates a depression has formed over the south-east Bay of Bengal.


It currently lays centred about 1070 km east-southeast of Chennai, 1030 km east-southeast of Puducherry and 720 km east-southeast of Trincomalee (Srilanka).


"The system is very likely to move west-northwestwards, intensify into a deep depression during next 24 hours and a cyclonic storm in subsequent 24 hours. It is very likely to cross north Tamil Nadu coast between Vedaranniyam and Chennai by the morning of December 2," the IMD said.


The IMD has advised fishermen not to venture into sea along and off Tamil Nadu and Puducherry coasts from the evening of November 30 onwards. Those at sea are advised to return to the coast.


Light to moderate rainfall at many places is very likely to commence over coastal Tamil Nadu from the evening of November 30.


The intensity would increase with rainfall at most places and "heavy to very heavy rainfall" at a few places over coastal Tamil Nadu and Puducherry and isolated "heavy to very heavy rainfall" over interior Tamil Nadu on December 1 and 2, the IMD said.


Light to moderate rainfall would occur at many places with isolated heavy falls very likely over Kerala on December 2 and 3.


"Squally winds speed reaching 45-55 kmph gusting to 65 kmph would commence to prevail along and off Tamil Nadu and Puducherry coasts from December 1. Sea condition would be rough to very rough along off Tamil Nadu and Puducherry coasts from December 1 onward," the IMD added.