Thane started to turn towards the west under the influence of a subtropical ridge of high pressure before its development slowed during December 27, as a strong outflow and marginally favourable sea surface temperatures fought with persistent vertical wind shear.
On December 23, the Joint Typhoon Warning Center (JTWC) reported that a tropical disturbance had developed within the monsoon trough about 1540 km (960 mi) to the east of Medan in Indonesia.
[7][8] As it was named, Thane started to turn towards the west under the influence of a subtropical ridge of high pressure before its development slowed as strong outflow and marginally favourable sea surface temperatures fought with persistent easterly vertical wind shear.
[17] Thane then made landfall as a borderline very severe cyclonic storm during December 30 on the north Tamil Nadu coast between Cuddalore and Puducherry.
The storm made Cuddalore inaccessible by damaging road network and the National Disaster Response Force and fire and rescue services had difficulty in reaching the cyclone affected fishing hamlets.
[19] Fishing activities had come to a complete halt in the cities of Chennai, Tiruvallur and Kanchipuram in the wake of the storm after the warnings by the weather department were received.
Chennai Corporation kept its four permanent relief centers (Basin Bridge, Chintadripet, Gopalapuram and Perambur Barracks Road) ready to accommodate people in case of evacuation due to torrential rains.