The IMD has forecast heavy rain across southern India on September 20.
Odisha, Chhattisgarh and Gangetic West Bengal may see heavy to very heavy rain.
Thunderstorms and lightning are expected over Bihar, Jharkhand and east Madhya Pradesh.
Delhi-NCR can expect rain and winds of 30 to 40 kmph.
People are advised to avoid open fields and electric poles.
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.
The weather department advises people to avoid open fields, trees and electric poles during thunderstorms and to check local bulletins before travelling.
The IMD has issued a heavy rainfall warning for Sunday, September 20, for parts of the Andaman and Nicobar Islands, Andhra Pradesh, Karnataka, Kerala, Tamil Nadu, Puducherry and Telangana.
Heavy to very heavy rainfall is forecast for parts of Odisha, Chhattisgarh, Gangetic West Bengal and the Andaman and Nicobar Islands.
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.
Rain clouds during the monsoon in Goa (representative image), Wikimedia Commons, CC BY-SA 2.0
