After a brief lull, heavy rains are expected to return to Tamil Nadu, Puducherry and Coastal Andhra Pradesh from the weekend.
Chennai and neighbourhood are just about limping back to normalcy after a sustained high-intensity rainfall that inundated large parts of the city during the past week.
Adjoining Kancheepuram and Tiruvallur districts were also battered by heavy rains resulting in severe flood conditions.
Army, Air Force and Naval personnel had joined the civil administration in rescuing marooned people at many places.
The fresh rain threat comes at a time when water has started draining in the low-lying areas in the city and suburbs following some let-up in the rains during the past few days. India Met Department has warned of heavy to very heavy rain on Saturday and Sunday for Tamil Nadu, Puducherry and Coastal Andhra Pradesh.
According to available forecasts, excess wet conditions could be replicated in the metropolis as a virulent rain-generating system approaches the coast in the next six days. It is expected to close in by Tuesday (December 1) but rains are expected to start pelting the coast from at least four days ahead from Friday.
The first week of December will remain extremely wet in the Chennai-Puducherry belt, according to the US Centre for Climate Prediction.
The probability of excess rain is high for the rest of Tamil Nadu as well as Sri Lanka, particularly its East Coast, the forecast said.