Mumbai, Sept. 28 -- With the monsoon refusing to bid the city farewell, the India Meteorological Department (IMD) has sounded a red alert on Sunday for Mumbai, Thane, Palghar and Raigad, warning of extremely heavy rainfall, thunderstorms, lightning and gusty winds at isolated places. The IMD said "Coastal districts like Ratnagiri and Sindhudurg, and the ghat regions of Nashik, are also expected to witness heavy showers." After a brief return of clear sunny skies, rains began again on Friday night and spilled over to Saturday, paving the way for a gloomy overcast weekend. From 8:30am to 5:30pm on Saturday, the IMD's Santacruz observatory recorded 22.4mm of rain, while the Colaba observatory recorded 9.6mm. In the 24 hour period before Saturday 8:30am, the Santacruz observatory had recorded 12mm of rainfall, and Colaba 54mm. As per the IMD, harsh monsoon seems to stem from a depression over the south coastal Odisha and the resultant trough. The IMD updated its forecast on Saturday afternoon, stating that compared to the coastal belt and parts of north Konkan, the rest of the state, including north Maharashtra, central Maharashtra, Marathwada and Vidarbha, was likely to receive only low-intensity rainfall on Sunday....