Tamil Nadu: Heavy rains expected in several districts on Dec 16 as new low-pressure system forms in BoB

A new low-pressure area is expected to form on December 16 in Bay of Bengal, bringing heavy rain to various districts in Tamil Nadu. Also, the existing low-pressure area over Lakshadweep and Maldives is likely to weaken. An atmospheric upper-level circulation over the South Andaman Sea may lead to the formation of a new low-pressure area on December 16, potentially moving towards the Tamil Nadu coast.

Tamil Nadu and Puducherry are expected to receive light to moderate rainfall with thunderstorms on December 14 and 15. Widespread light to moderate rain is anticipated on December 16, 17, and 18, with isolated showers on December 19. Heavy rain is likely in several districts, including Thanjavur, Thiruvarur, Nagapattinam, Mayiladuthurai, Ramanathapuram, Pudukkottai, and Karaikal on December 16. Heavy to very heavy rainfall is expected in Cuddalore, Mayiladuthurai, and Karaikal on December 17. 

Heavy rainfall is expected in delta districts, Cuddalore, Villupuram, Ariyalur, Perambalur, Kallakurichi, Chengalpattu, Thiruvannamalai, and Kanchipuram districts on December 18. Chennai and its suburbs are likely to experience partly cloudy skies with light rain and thunderstorms in some areas. As of December 13, Tamil Nadu has received 54 cm of rainfall since October 1, which is 32% higher than the average of 40 cm.

Tamil Nadu has received 54 cm of rainfall from October 1 to December 13, exceeding the average of 40 cm by 32%. As of December 12, the rainfall was 16% above average, with a significant increase in a single day.