Tamil Nadu, including Chennai, is bracing for heavy to very heavy rainfall from a deep depression over the Bay of Bengal. The India Meteorological Department (IMD) has issued orange alerts for districts like Tiruvarur, Nagapattinam, and Cuddalore, and yellow alerts for Chennai and others. The system is expected to cross Sri Lanka's coast before weakening, but will bring widespread rain, thunderstorms, and squally weather to coastal and delta regions. Authorities advise caution due to potential flooding and disruptions.