India Meteorological Department (IMD) Director General K J Ramesh said monsoon is in an "active phase" and has reached Mumbai, Mahabaleshwar (in Maharashtra) and several parts of the Konkan region, apart from Bijapur district in north Karnataka.
"There is also a low-pressure area in the Bay of Bengal and this will take the monsoon to several parts of West Bengal. The coming week will be very good for the advance of monsoon on the western side and east India," Ramesh said.
However, there will be no significant change in maximum temperatures over most part of the country during the next 24 hours and mercury is likely to rise by 2-3 degrees Celcius over plains of northwest India thereafter.
The monsoon reached Kerala on May 30, two days ahead of its normal schedule.
"Favourable conditions are developing for further advance of southwest monsoon into some more parts of central Arabian Sea, Konkan, Madhya Maharashtra. It is expected to advance to interior Karnataka and remaining parts of Rayalaseema, some parts of Telangana and some more parts of Coastal Andhra Pradesh, central and north Bay of Bengal, Tripura, Assam and Meghalaya and some more parts of West Bengal and Sikkim during next 2-3 days," the IMD said.
It also predicted "heavy to very heavy rainfall" at isolated places over Assam and Meghalaya, Konkan and Goa and Coastal Karnataka tomorrow and "heavy" rains over West Bengal and Sikkim, Arunachal Pradesh, Nagaland, Manipur, Mizoram & Tripura, central Maharashtra, Marathwada and Kerala.