The met department on Wednesday forecast "extremely heavy rainfall" on Thursday in Mumbai and adjoining Raigad district.
The Indian Meteorological Department (IMD) has issued a red rain alert, indicating "extremely heavy rainfall", for Mumbai and Raigad districts, said an IMD official.
This indicates a precipitation of more than 204 mm in 24 hours starting Thursday morning, he said.
However, Mumbai would receive heavy rainfall on Friday, but Raigad will continue to receive extremely heavy showers that day also, the official said.