The southwest monsoon advanced into most parts of Gangetic West Bengal, Jharkhand and Bihar on Sunday, the Met department said, forecasting heavy rain in the next two days.

The weatherman said that conditions are favourable for the monsoon's advancement into the remaining portion of Gangetic Bengal and Jharkhand over the next three days.

With the monsoon setting in, West Bengal, Bihar and Jharkhand are likely to receive isolated heavy rainfall on Monday and Tuesday, the weatherman said.

The Met has also forecast heavy to very heavy rainfall in sub-Himalayan West Bengal and Sikkim.

Thunderstorms with lighting are likely in Kolkata in the next few days.

The city sky was overcast throughout the day on Sunday with one or two spells of light rain.