Today (29.11.2021)
Thunderstorm with heavy to very heavy rain is likely to occur at isolated places over Kanyakumari and Tirunelveli districts.
Thunderstorm with heavy rain is also likely to occur at isolated places over Thoothukudi and Ramanathapuram districts.
Thunderstorm with moderate rain is likely to occur at most places over rest Coastal Tamilnadu.
Light to moderate rain is also likely to occur at most places over Interior Tamilnadu districts.

Tomorrow (30.11.2021)
Thunderstorm with heavy rain is likely to occur at isolated places over Kanyakumari, Tirunelveli and Ramanathapuram districts.
Thunderstorm with moderate rain is likely to occur at many places over rest South Tamilnadu districts.
Light to moderate rain is also likely to occur at most places over North Tamilnadu districts.

HEAVY RAINFALL WARNING:

Today(29.11.2021):Heavy to very heavy rain is likely to occur at isolated places over Kanyakumari and Tirunelveli districts.
Heavy rain is also likely to occur at isolated places over Thoothukudi and Ramanathapuram districts.

Tomorrow(30.11.2021): Heavy rain is likely to occur at isolated places over Kanyakumari, Tirunelveli and Ramanathapuram districts.

THUNDERSTORM WARNING:
Thunderstorm with lightning is likely to occur at isolated places overTamil Nadu.

LOCAL FORECAST FOR CHENNAI CITY AND NEIGHBOURHOOD:
For next 24 HRS: Sky condition is likely to be generally cloudy. Thunderstorm with light to moderate rain islikely to occur in some areas.

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