Met officials said, the low-pressure that lay over southwest Bay of Bengal has weakened, but thunderstorm with lightning is also likely in south coastal Tamil Nadu.
Kancheepuram, Puducherry, Villupuram, Cuddalore, Thiruvannamalai, Nagapattinam, Karaikal, Ariyalur among others districts have been predicted to receive heavy rainfall.
The Regional Meteorological Centre also warned fishermen against venturing into the sea in certain areas following the likelihood of rough seas.
Indian Meteorological Department said that heavy rain is very likely at isolated chunks in Tamil Nadu and Kerala during the period.
Thunderstorm, accompanied with lightning and gusty winds, is very likely to occur at isolated places over Tamil Nadu and Kerala during next 24 hours, IMD said.
Heavy rain is very likely at isolated expanse of Andaman & Nicobar Islands, Tamil Nadu, coastal Karnataka and Kerala during the period.
The Indian Meteorological Department told media that there was no likelihood of a tsunami forming due to Cyclone Ockhi in the Bay of Bengal region, dispelling fake news alerts and rumours on WhatsApp.
Thousands of fishermen and their families in Kerala and Tamil Nadu are continuously holding mass protests, demanding for search operations to continue and for relief to be provided faster.
The State Disaster Management Authority has issued an alert for Thiruvananthapuram, Kollam, Pathanamthitta, Idukki and Kottayam districts.
Puducherry continued to be lashed by heavy rains with government authorities declaring holiday for all schools in the region today.
Chennai received 36 cm of rains in the last three days, the AIADMK leader said, adding, the government acted "quickly" to ensure there was no water stagnation in the city.
With the northeast monsoon remaining active over the state, the Meteorological Department has forecast heavy rains for the next two days.