The Met department on Sunday issued a red alert of extremely heavy rainfall on Monday at isolated places in Pune and Satara districts in Maharashtra, an official said.
The forecast also predicted heavy rainfall at isolated places in Mumbai, Raigad, and Palghar from Monday onwards, he said, adding that the intensity of rains would reduce from Tuesday.
The IMD classifies minimum 204.5 mm rainfall in 24 hours as extremely heavy.
A red alert requires authorities to take preventive steps to minimise damage.
"Districts in Western Maharashtra, including Pune, Kolhapur, Satara and Sangli, are expected to receive strong spells of showers in the week beginning Monday (August 17).
"Satara and Pune districts are very likely to receive extremely heavy rainfall at isolated places on Monday," the India Meteorological Department (IMC) official said.
He said rest of the region is expected to receive heavy to very heavy rainfall at isolated places during the week.
Parts of Maharashtra including north, Madhya and Vidarbha regions are expected to receive heavy to very heavy showers till Thursday, he added.