Sunday’s deep depression over West-central Bay of Bengal has started weakening, and had become a depression by Monday afternoon.
The system has moved slightly westwards and lay centred about 650 km East-north-east of Chennai, the India Meteorological Department (IMD) said.
The system would move West and then South-westward towards South Andhra Pradesh and North Tamil Nadu coasts and weaken further on Tuesday. US Navy Joint Typhoon Warning Centre noted that the process of convection (cloud-building) around the system had more or less ceased and wind speeds diminished.
High vertical wind shear (change in wind speeds higher in the atmosphere) has hit its tower structure.
Wind shear lops off the storm head.
Dry continental air feeding into the system also will lead to the disintegration of the system.
But the US forecaster said that the system will be closely watched for signs of regeneration over seawaters.
Satellite pictures on Monday afternoon showed rain-bearing clouds rising over parts of North-east and adjoining East-central Bay of Bengal and Andaman Sea.
Less productive clouds were scattered over east, northeast and extreme south peninsular India.
Forecast valid until Thursday said that thundershowers would break out over coastal Andhra Pradesh on Tuesday.
Over Tamil Nadu and Kerala, rains have been forecast on two subsequent days, which may scale up in intensity thereafter.
Thundershowers have been forecast also over remaining parts of peninsular India from Wednesday onwards.
An extended outlook valid until Monday said that rain or thundershowers are likely over Odisha and south peninsular India.
Some global models saw a fresh easterly wave over the Bay of Bengal bringing rains to Sri Lanka and adjoining southeast Tamil Nadu during the last week of this month.
As for the north, a fresh weather-setting western disturbance has been forecast to start impacting western Himalayan region from Wednesday onwards.
Rain or snow is likely at one or two places over Jammu and Kashmir.
No significant fog conditions are expected to develop over northwest India during the next two days.
Maximum and minimum temperatures are expected to fall during next three days.