Why southern states are receiving heavy rain now

Heavy to very heavy rain has been reported in Tamil Nadu, Puducherry, Coastal Andhra Pradesh, Rayalaseema, and Kerala and parts of Karnataka. Why is it raining in these southern states now?
The reason is the northeast monsoon.
According to the India Meteorological Department (IMD), Tamil Nadu receives at 48 per cent of its annual rainfall from northeast monsoon. The southwest monsoon, which generally enters from Kerala in June and spreads the rain spells across the country, ends in October.
This year’s southwest monsoon officially exited India on October 15. But the southern states receiving the heavy showers is due to the northeast monsoon, which contributes to 11 per cent of India’s annual rainfall, according to IMD.
A well-marked low-pressure area over the central Bay of Bengal is expected to intensify into a depression as it moves west-northwest towards the states in the south along the Bay of Bengal coastline.

These heavy rains have signalled the beginning of the northeast monsoon season. Heavy rain in Chennai prompted authorities to declare a holiday for educational institutions on Tuesday.
Educational institutions in Chennai and Bengaluru will be closed as heavy rain is expected. The region is also experiencing easterly and northeasterly winds, helping form rain-bearing clouds.
Meanwhile, a depression over the west-central Arabian Sea is moving northwest at 18 kmph and is expected to weaken as it nears Oman’s Masirah coast.
Cyclonic circulations are also active over northeast Bangladesh and the Sub-Himalayan areas of West Bengal and Sikkim, though activity near south Assam has decreased.