Weather tomorrow: IMD forecasts heavy rain in 5 states; yellow alert in 17 Tamil Nadu districts while Delhi, Northeast to remain dry. Heavy rain and thunderstorms are expected across south India, especially in Tamil Nadu, from October 21. A yellow alert has been issued for 17 districts, indicating severe weather conditions and possible heavy rainfall. Kerala and Karnataka also anticipate widespread rainfall and threatened conditions with gusty winds and thunderstorms. Residents are advised to stay.