The IMD has issued a heavy rainfall warning for Kerala, Karnataka, Tamil Nadu, Andhra Pradesh, Telangana and Puducherry on September 20.
Tamil Nadu may see isolated heavy rain with thunderstorms and gusts of 40 to 50 kmph.
Strong surface winds are very likely over parts of Andhra Pradesh and Telangana.
The Andaman and Nicobar Islands are also under a heavy rain warning.
Heavy to very heavy rain is expected over Odisha, Chhattisgarh and Gangetic West Bengal.
Fairly widespread monsoon showers with thunderstorm and lightning activity are expected over Bihar, Jharkhand and east Madhya Pradesh.
Thunderstorms and lightning are also forecast over Marathwada, sub-Himalayan West Bengal, east Rajasthan, Konkan and Goa, and parts of the Northeast.
Reports counting the states affected by rain, thunderstorms and strong winds on Sunday put the number at 18, including Delhi, Uttar Pradesh, Bihar and Rajasthan.
Strong surface winds are very likely over parts of Andhra Pradesh and Telangana, while Tamil Nadu may see gusts of 40 to 50 kmph with isolated heavy rain.
Winds of up to 60 to 65 kmph are possible in vulnerable areas, according to a forecast summary.
Delhi-NCR is forecast to see rain and thunderstorms with winds of about 30 to 40 kmph, with a maximum temperature near 34 degrees Celsius and a minimum near 24 degrees Celsius.
Lucknow is expected to reach about 34 degrees Celsius with a minimum near 26 degrees, and rain in Uttar Pradesh may extend into September 21.
Patna is forecast to see a maximum of about 34 degrees Celsius and a minimum near 27 degrees Celsius, with widespread thunderstorms across Bihar.
Heavy rain in hilly areas may cause landslides and disrupt travel, and lightning and hail are possible in the hills.
The overall pattern is driven by an active southwest monsoon over central, eastern and southern India during the season’s withdrawal phase.
Rain clouds during the monsoon in Goa (representative image), Wikimedia Commons, CC BY-SA 2.0
