Coastal Andhra Pradesh and Rayalaseema bore the brunt as a rain-generating low-pressure area lay anchored half over land and half into the sea off South Andhra Pradesh coast on Wednesday.
Elsewhere, the North-East Monsoon was active over south interior Karnataka and Kerala during the 24 hours ending in the morning.
The low-pressure area will track slowly west-north-west across the rest of Andhra Pradesh and Karnataka and enter the Arabian Sea by Friday, an India Meteorological Department (IMD) update said.
The Climate Prediction Centre of the US National Weather Services too noted “a low-pressure system tracking west from the Bay of Bengal”.
Above-average rainfall is favoured along the westward track of this system as it crosses south-central India, the US agency said.
“It should be noted that a low chance for tropical cyclone development exists across the north-east Arabian Sea when this system moves offshore from the west coast of India,” the US agency said.
An IMD warning said that heavy to very heavy rainfall would lash Coastal Andhra Pradesh and Rayalaseema until Thursday morning. Heavy rainfall would also occur at isolated places over Odisha, Telangana, coastal Karnataka, north interior and south interior Karnataka.
Forecast valid until Friday morning said that the heavy rain belt will stand pat over Coastal Andhra Pradesh and Rayalaseema but associated rain bands will extend to Telangana and the whole of Karnataka.
Almost similar weather pattern is likely to pan out during the 24 hours that ends on Saturday morning as well.
Meanwhile, Odisha and Gangetic West Bengal to the north-east also witnessed overnight rains until Wednesday morning.
The Climate Prediction Centre of the US National Weather Services said that the east and west coasts will receive varying amounts of rainfall during the week ending October 29.
Above-normal rainfall has been indicated for Gujarat, Andhra Pradesh and Odisha.
But north coastal Tamil Nadu and entire Andhra Pradesh may experience below normal rainfall during the subsequent week (October 30 to November 5).
This period may also see the north-west Rajasthan and Punjab receive its first wave of showers of the rabi season, says the US agency.