New Delhi, Nov 10 : A well-marked low pressure area over southeast Bay of Bengal is expected to concentrate into a depression by Wednesday evening and bring in more rainfall to Tamil Nadu and south Andhra Pradesh that have been inundated with copious rains already for the past three days, the India Meteorological Department (IMD)said on Wednesday. "The Low Pressure Area (LPA) over southeast Bay of Bengal lay as a well-marked Low Pressure Area over southeast and adjoining southwest Bay of Bengal at 5:30 a.m. By 8:30 a.m., it lay over central parts of the south Bay of Bengal. It is likely to concentrate into a depression over Southwest Bay of Bengal during next 12 hours, move west-northwestwards and reach near north Tamil Nadu coast by Thursday early morning," the IMD said in a statement. Thereafter, it is likely to continue to move west-northwestwards and cross north Tamil Nadu and adjoining south Andhra Pradesh coast between Karaikal & Sriharikota around Cuddalore by Thursday evening. As a result, large parts of Tamil Nadu, especially the northern coastal areas and southern Andhra Pradesh, are experiencing extremely heavy rainfall. More than two dozen places across Tamil Nadu and Puducherry received significant rainfall of more than 100 mm during the last 24 hours ending at 8:30 am on Wednesday, the statement said. The IMD's area cyclone warning department at Chennai's statement said, Cuddalore, Pudukottai, Villupuram, Ramanathapuram, Sivaganga, Puducherry, and Karaikkal areas would receive rains on Wednesday while on Thursday, heavy to very heavy rains are expected in Chennai, Tiruvallur, Kancheepuram, Villupuram, Chengalpattu, and Tiruvannamalai districts. The weather body has also warned that the whole of Western Tamil Nadu will receive spells of rain and from November 11 onwards, the rains would recede. Significant amount of rainfall was received from 8:30 am on Tuesday till 8:30 am on Wednesday. While Nagappattinam experienced 310 mm rainfall, Thirupoondi - 306 mm, Karaikal - 287 mm, Thalanayar - 236.2 mm, Atiramapattinam - 129 mm, Cuddalore - 98 mm, M.O Pondicherry received 95 mm and Chennai's Nungambakkam 27 mm. /IANS