The depression lay centred 450 kms east southsast of Chennai and is expected to turn into a cyclonic storm and cross the Tamil Nadu coast between Karaikal and Chennai by tomorrow night, a Met department official said.
Under its influence, rainfall is expected in most parts of Tamil Nadu with heavy to very heavy rainfall over north coastal Tamil Nadu and Puducherry in the next 24-48 hours, the official said.
Fishermen in Tamil Nadu have been advised not to venture out to sea in the next 24 to 48 hours "as the sea will be rough to very rough," the official said.
The northeast monsoon, which has brought the wet spell, had set in over the southern region on October 29.