CHENNAI: Cyclonic Storm Ditwah over the southwest Bay of Bengal continued its slow north-northwesterly drift on Saturday, delivering heavy rainfall across coastal Tamil Nadu. Moving at a sluggish 8–10 kmph, the system remained nearly stationary for several hours, positioned about 220 km south-southeast of Puducherry and 330 km south of Chennai.
According to the Regional Meteorological Centre (RMC), Chennai, the system is very likely to persist on its north-northwestward track and approach the southwest Bay, close to the north Tamil Nadu–Puducherry–south Andhra Pradesh coast, by early Sunday. As it skirts the shoreline, Ditwah is expected to come within 50 km of the Tamil Nadu coast by early Sunday and close to 25 km by evening.
By Saturday afternoon, the cyclone showed clear signs of weakening. Its core appeared exposed and the convective structure significantly disrupted after traversing the Sri Lankan landmass. Intrusion of dry air further eroded the system’s organisation. Although a brief window of night-time intensification exists, forecasts suggest the system may continue to drift up the coast in its present weakened state.
Despite this weakening trend, the IMD retained the red and orange alerts already issued, cautioning that Ditwah would continue to bring heavy to very heavy rainfall to several coastal districts.
Rainfall activity is likely to persist till December 1. Delta districts have already borne the brunt, with Nagapattinam experiencing intense spells since Friday. Coastal pockets recorded between 175 and 250 mm as feeder bands repeatedly struck the shoreline. For the KTCC region—Kancheepuram, Tiruvallur, Chennai and Chengalpattu—the most significant rainfall is expected on Sunday.
The forecast indicates very heavy to extremely heavy rainfall over Tiruvallur and Ranipet on November 30, while Chennai, Kancheepuram, Chengalpattu, Vellore and Tirupattur too may receive very heavy spells. Isolated heavy showers are likely over Tiruvallur on December 1, marking the final phase of Ditwah-linked rainfall.