Yesterday’s Depression over southwest Bay of Bengal moved west-northwestwards and lay centered at 0830 hrs IST of 11th November 2021, over southwest & adjoining west-central Bay of Bengal, near Lat. 12.3°N and Long. 81.2°E, about 130 km east-southeast of Chennai and 150 km east-northeast of Puducherry. It is very likely to continue to move west-northwestwards and cross north Tamil Nadu & adjoining south Andhra Pradesh coasts around Chennai during the evening of today, the 11th November 2021.

Thunderstorm with scattered heavy to very heavy with isolated extremely heavy rain is likely to occur over Chennai, Tiruvallur, Kancheepuram and Ranipettai districts of Tamilnadu.

Thunderstorm with heavy to very heavy rain is likely to occur at isolated places over Vellore, Tirupattur, Tiruvannamalai, Villupuram and Chengalpattu districts of Tamilnadu.

Thunderstorm with heavy rain is also likely to occur at isolated over Krishnagiri, Erode, Salem, Dharmapuri and Kallakurichi districts of Tamilnadu.

Moderate rain is likely to occur at most places over rest districts of north Tamil Nadu, Puducherry & Karaikal area.
Light to moderate rain is likely to occur at most places over districts of south Tamilnadu.

Reference: http://imdchennai.gov.in/tn_fc.pdf
http://www.imdchennai.gov.in/hrw_district.htm