The depression is likely to intensify further into a deep depression during the next 12 hours.
Pre-cyclone watch was issued for Andhra Pradesh coast on Thursday by Union Ministry of Earth Science, adding that a depression has formed over the southeast Bay of Bengal.
"It is very likely to intensify further into a deep depression during the next 12 hours and into a cyclonic storm during the subsequent 24 hours. It is very likely to move northwestwards towards Andhra Pradesh and adjoining north Tamil Nadu coast during next 72 hours," said the ministry in a statement.
"Latest satellite imageries and surface observations indicate that a depression has formed over the southeast Bay of Bengal and lay centred at 0530 hrs IST of today, 13th December, 2018 near latitude 6.5 degree North and longitude 88.7 degree East, about 850 km east-southeast of Trincomalee (Sri Lanka), 1170 km southeast of Chennai (Tamil Nadu) and 1350 km south-southeast of Machilipatnam (Andhra Pradesh)," the ministry added.