Between 8.30 am and 11 am, the IMD's Colaba observatory (representative of south Mumbai) recorded 79.4 mm rainfall, while the Santacruz observatory (representative of suburbs) recorded 44.5 mm rain, she said.
The orange alert implies that authorities should be ready to handle situations arising out of severe weather.
Moderate to heavy showers will continue over Mumbai for next 48 hours.
Tropical storm 'Tauktae' (pronounced as Tau'Te) which had intensified into a very severe cyclonic storm, lies close to the Gujarat coast, the India Meteorological Department said. "The landfall process has started and will continue during next two hours," the IMD said.