Today (31.12.2021)
Thunderstorm with moderate rain is likely to occur at most places over Coastal districts of Tamilnadu and at a few places over interior districts of Tamilnadu.
Heavy to very heavy is likely to occur at one or two places over Delta districts,Nagapattinam, Villupuram, Cuddalore, Chengalpattu, Kancheepuram,Chennai, Tiruvallur districts of Tamilnadu, Puducherry & Karaikal area.

Tomorrow (01.01.2022)
Thunderstorm with moderate rain is likely to occur at most places over Coastal districts of Tamilnadu and at a few places over interior districts of Tamilnadu.
Heavy to very heavy rain is likely to occur at one or two places over delta districts, Villupuram, Cuddalore, Chengalpattu, Kancheepuram, Chennai, Tiruvallur districts of Tamilnadu, Puducherry & Karaikal area.

HEAVY RAINFALL WARNING:

Today (31.12.2021):
Heavy to very heavy rain is likely to occur at one or two places over Delta districts, Nagapattinam, Villupuram, Cuddalore, Chengalpattu, Kancheepuram, Chennai, Tiruvallur districts of Tamilnadu, Puducherry & Karaikal area.

Tomorrow (01.01.2022):
Thunderstorm with heavy to very heavy rain is likely to occur at one or two places over delta districts, Villupuram, Cuddalore, Chengalpattu, Kancheepuram, Chennai, Tiruvallur districts of Tamilnadu, Puducherry & Karaikal area.

THUNDERSTORM WARNING:
Today (31.12.2021) & Tomorrow (01.01.2022): Thunderstorm with lightening is likely to occur at isolated places over Tamilnadu.

LOCAL FORECAST FOR CHENNAI CITY AND NEIGHBOURHOOD:

For next 24 HRS:
Sky condition is likely to be generally cloudy. Thunderstorm with heavy to very heavy rain is likely to occur at one or two places.
Maximum and minimum temperature is likely to be around 30˚C and 21˚C respectively.

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