Andhra-Odisha Coast On Alert As Bay System Brings Heavy Rain From Sept 22

A low-pressure area over the north Andaman Sea and adjoining Bay of Bengal is likely to intensify into a depression on September 21 and a deep depression by September 22, bringing a fresh spell of heavy to very heavy rain to Andhra Pradesh as the system moves towards the coast.

The system developed under the influence of an upper-air cyclonic circulation that moved westwards from the region of North Thailand into the North Andaman Sea. Once over the Bay, the disturbance is drawing moisture from the warm ocean, while the monsoon circulation is helping organise clouds, thunderstorms and rising air. The release of heat as moisture condenses can further strengthen the circulation, allowing the low-pressure area to deepen.

The system is expected to move west-northwestwards and reach the west-central and adjoining northwest Bay of Bengal near the south Odisha-north Andhra Pradesh coast around September 23. The IMD has forecast very heavy rainfall over Coastal Andhra Pradesh on September 22, 23 and 24, followed by heavy rain on September 25.

Strong winds are also expected near the coast, with winds of 55-65 kmph gusting to 75 kmph possible around September 23. Sea conditions are likely to become rough to very rough, and fishermen have been advised not to venture into the affected waters.

Several parts of Andhra Pradesh have already received rain. Vepada in Vizianagaram recorded 6 cm, while Racherla in Prakasam received 5 cm and Addanki in Bapatla 4 cm in the latest spell. Rayalaseema is also likely to see thunderstorms, lightning and strong winds.

The developing system is significant, but its formation is not unusual for September. Low-pressure systems are a regular feature of the southwest monsoon, although their number and intensity vary from year to year. IMD records show that September 2025 produced four such systems, including a deep depression and a depression.

The distinction is important: the current forecast is for a deep depression, not a cyclone. Its final intensity will depend on how favourable atmospheric and oceanic conditions remain as it approaches the Andhra-Odisha coast.

For Andhra Pradesh, the system could provide substantial rainfall at a time when rainfall distribution remains uneven, while also bringing the risks of waterlogging, lightning, strong winds and rough seas along the coast.