New Delhi, Nov 10 : A depression lay centred over southwest Bay of Bengal, about 430 kms east-southeast of Chennai, resulting in moderate to heavy to extremely heavy rainfall along the Tamil Nadu coast on Wednesday, the IMD said. "The well-marked low pressure area over central parts of south Bay of Bengal moved west-northwestwards and concentrated into a depression and lay centred at 5.30 p.m. over southwest Bay of Bengal about 430 km east-southeast of Chennai and 420 km east-southeast of Puducherry," the India Meteorological Department (IMD) said. This depression is very likely to move west-northwestwards and reach near the north Tamil Nadu coast by the early morning on Thursday and thereafter, likely to continue to move west-northwestwards and cross north Tamil Nadu and adjoining south Andhra Pradesh coasts between Karaikal and Sriharikota close to the north of Puducherry by Thursday evening, it said. Light to moderate rainfall has been predicted at most places with heavy to very heavy rainfall at a few places and extremely heavy falls at isolated places very likely over north coastal Tamil Nadu, Puducherry, north interior Tamil Nadu, south coastal Andhra Pradesh and Rayalaseema and heavy rainfall at isolated places over south interior Karnataka. Tamil Nadu and southern Andhra Pradesh have already been battered by rains for at least three days with several places in the former state witnessing massive flooding. National Disaster Response Force (NDRF) teams have been deployed at multiple places to deal with any exigencies. There would be squally winds with speed reaching 45-55 kmph gusting to 65 kmph over southwest and adjoining west-central Bay of Bengal and along and off Tamil Nadu, Puducherry and south Andhra Pradesh coasts on Thursday, the IMD said. Sea condition will be rough to very rough over southwest and adjoining west-central Bay of Bengal and along and off Tamil Nadu, Puducherry and south Andhra Pradesh coasts during on Thursday and hence, fishermen have been advised not to venture into southwest and adjoining west-central Bay of Bengal and along and off Tamil Nadu, Puducherry and south Andhra Pradesh coasts. /IANS