A low-pressure system over the southeast Bay of Bengal is set to bring heavy rainfall to Tamil Nadu, particularly in delta and north districts. The Chennai Meteorological Centre has issued orange and yellow alerts. Very heavy rain, up to 20 cm, is expected in areas like Cuddalore, Nagapattinam, Thanjavur, Mayiladuthurai, and Karaikal. Rainfall could intensify in Puducherry and surrounding districts today.