Under the influence of cyclonic circulation over the Southeast Bay of Bengal (BoB), a low-pressure area formed over the same region. This system has become well-marked and also moved to central parts of South BoB. It is likely to strengthen into a depression/deep depression in the next about 24 hours and move west-northwest and come closer to the east coast of Sri Lanka, over Southwest BoB.
Extremely heavy rainfall activity will remain confined to the sea region over the next 36 hours or so. Moderate rain and thundershowers, interspersed with heavy rainfall at few places are likely over South Coastal Andhra Pradesh and Coastal Tamil Nadu during this period. Environmental conditions and sea surface temperature are quite favourable for further intensification of the weather system.
It will be confirmed, very soon, whether the system becomes a tropical storm, off the Tamil Nadu coast, over Southwest BoB. Heavy to very heavy rainfall is expected to lash the coastline of Tamil Nadu from Chennai to Kanyakumari. The central parts of the coast covering Puducherry, Karaikal, Nagapattinam, Tondi, and Tuticorin will be at risk of flooding rains, commencing 15th October late at night and continuing on 16th October, through the day and night. The heavy rainfall belt will cover the interior parts of the state as well, stretching up to Trichy, Madurai, Thanjavur, Erode, Karur, Tirupur, Coimbatore and Ooty.
The extreme rainfall belt will travel across the South Peninsula and impact most parts of Kerala, on the 16th & 17th. Kochi, Kannur, Thrissur, Kozhikode, Wayanad and Idukki will be lashed with very heavy and damaging rainfall during this period. Even Coastal Karnataka and South Interior Karnataka will get scattered moderate to heavy rainfall. Bengaluru, Mysuru, Mandya, Mangaluru and Karwar will also receive spells of heavy rains on 16th and 17th October. The weather conditions will improve from the 18th of Oct onward when the weather system moves across the South Peninsula and enters the Arabian Sea.