Due to the expected formation of a "vortex" of low pressure over the North Konkan Coast by Saturday evening, heavy rains can be expected in Mumbai, and Konkan from Saturday thru Sunday and Monday. On Saturday, Mumbai could recieve about 75mm of rain, 120mm on Sunday/Monday. Some stations in Konkan can get upto 200 mms per day.
Mahableshwar can also see the commencement of "real" heavy rains from Sunday thru Thursday, at least.
The rain are likely to move eastwards towards interior Maharashtra from Monday. Yet another low pressure circulation is forecasted in the Vidharbha/Madhya Maharashtra region from Tuesday. Hence, very good rains are expected in Maharashtra from Monday/Tuesday.
Madhya Maharashtra regions may recieve 50-60mms of rain per day from Monday for a couple of days.( Mahableshwar may get upto 400 mms in these 2 days).