New Delhi | A fresh heat wave may commence over east India from Saturday while rainfall and thunderstorm activity will continue in the country's northwest and central parts during the next four-five days, the IMD said on Friday.

The Met office also warned of heavy rainfall, accompanied by thunderstorms and lightning, over the northeast from Saturday to May 13.

The India Meteorological Department (IMD) said heatwave conditions were very likely in isolated pockets of sub-Himalayan West Bengal and Sikkim during May 11-12, Gangetic West Bengal during May 10-14, Bihar and Odisha during May 11-14, Jharkhand during May 12-14 and east Uttar Pradesh on May 14-15.

Earlier this month, the IMD had said most parts of India might see above-normal temperatures in May but occasional thunderstorms could keep the heat from reaching last year's severity levels.

IMD Director General Mrutyunjay Mohapatra had said most parts of the country were likely to receive normal to above-normal rainfall, except some areas in the northwest, central and northeast.

The country recorded 72 heatwave days in April, Mohapatra had added.

Above-normal heatwave days were reported in Rajasthan and Gujarat (six to 11 days), and in east Madhya Pradesh and Vidarbha (four to six days) in April, compared to the usual two to three days.

In east-central India, Maharashtra and adjoining parts of northern Peninsular India recorded one to three heatwave days, slightly below the normal of two to three days.