The India Meteorological Department (IMD) confirmed that a deep depression over the Bay of Bengal has weakened into a depression, significantly influencing weather patterns across Tamil Nadu and Puducherry in early January 2026. This system was very likely to move west-northwestwards and cross the north Sri Lanka coast between Trincomalee and Jaffna as a depression around January 10th. Consequently, the IMD issued forecasts for heavy to very heavy rainfall at isolated places over various districts of Tamil Nadu until January 11. Orange alerts were sounded for districts such as Thiruvarur, Karaikal, and Nagapattinam, indicating the possibility of very heavy rainfall. A yellow alert was issued for several other areas, including Chennai, Thanjavur, Sivagangai, Madurai, and Tiruchirappalli, warning of heavy rain. Coastal districts like Chennai, Chengalpattu, Tiruvallur, Kancheepuram, and Villupuram were specifically mentioned as likely to experience intense rainfall, leading to potential waterlogging and traffic disruptions, particularly in low-lying urban areas. Authorities also advised fishermen not to venture into the southwest Bay of Bengal, Gulf of Mannar, and adjoining areas along the Tamil Nadu and Puducherry coasts due to rough to very rough sea conditions and squally weather. This weather event was noted as an unusual January system for the Bay of Bengal, an area that has historically witnessed a limited number of intense weather systems during this month.