The Depression over southwest Bay of Bengal off north Tamil Nadu is very likely to continue to move west-northwestwards and cross between Puducherry and Chennai by early Friday, said the Indian Meteorological Department (IMD).
The weather department has predicted moderate rainfall at most places and heavy to very heavy rainfall at few places and extremely heavy falls at isolated places very likely over Tamil Nadu, Puducherry and Karaikal.
The IMD has also forecast heavy to very heavy rainfall and extremely heavy falls at isolated places over adjoining districts of Rayalaseema and heavy to very heavy rainfall at isolated places over south coastal Andhra Pradesh and south interior Karnataka for Thursday.
For Friday, the IMD has said light to moderate rainfall at most places with heavy to very heavy rainfall very likely over Tamil Nadu, Puducherry and Karaikal and coastal Andhra Pradesh and heavy rainfall at isolated places over Rayalaseema and Karnataka.
Squally wind speed reaching 45-55 kmph gusting to 65 kmph likely to prevail over southwest and adjoining west-central Bay of Bengal and along and off Tamil Nadu, Puducherry and adjoining south Andhra Pradesh coasts during next 24 hours and decrease gradually thereafter, the IMD said.
The sea condition will be rough and the fishermen have been warned not to venture into the sea.
According to the Tamil Nadu government, surplus water from Redhills lake, Cholavaram, Chembarambakkam and Poondi are being released.
In order to meet the flood situation in Chennai, 54 boats, 793 giant water pumps and 46 excavators are kept ready.
In other districts, tree cutting machines, excavators, water pumps, generators and others are kept ready, the government said.
The government said 2,156 persons have been housed in 36 relief centres in nine districts and in Chennai 839 persons are housed in five relief centres.
Those affected by rains can complain at toll free 1077, TNSMART website and WhatsApp number 9445869849.