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.