A cyclonic storm is probably going to strike Tamil Nadu coast between Vedaranniyam and Chennai the India Meteorological Department said.
Based on Cyclone Warning Division of the IMD, satellite imagery indicates a depression has formed over south-east Bay of Bengal.
It currently sets centred about 1070 kilometres east-south-east of Chennai, 1030 kilometres east-south-east of Puducherry and 720 km east south-east of Trincomalee (Srilanka).
"The system is most likely to move west-northwestwards, intensify into a deep depression during next 24 hours and a cyclonic storm in subsequent 24 hours. It truly is very prone to cross north Tamil Nadu shore between Vedaranniyam and Chennai from the morning of December 2," the IMD said.
The IMD has counselled 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 come back to the coast.
Light to moderate rain at many locations is very possible to commence over coastal Tamil Nadu.
The intensity would grow with rain in most areas and "heavy to very heavy rain" at several places over coastal Tamil Nadu and Puducherry and apart "significant to very heavy rain" over interior Tamil Nadu on December 1 and 2, the IMD said.
Light to average rainfall would happen at many places with isolated heavy falls quite likely over Kerala on 3 and December 2.
"Squally winds rate was reaching 45-55 mph gusting to 65 mph would commence to endure along and off Tamil Nadu and Puducherry coasts from December 1. Sea state will be rough to very rough along off Tamil Nadu and Puducherry coasts from December 1 on," the IMD added.