City records 91mm rainfall, wettest Dec day ever
MUMBAI: The India Meteorological Department’s (IMD) Santacruz observatory recorded 91mm rainfall in the past 24 hours at 8:30am Thursday, marking the city’s highest-ever single-day rainfall during December. Mumbai’s previous record stood at 53.8mm of rain in 24 hours, on December 6, 2017, due to the passage of Cyclone Ockhi, close to the city coast.
The mean monthly rainfall for December (i.e. the average from 1981 to 2010) stands at just 1.6mm. The ongoing unseasonal rains are due to a cyclonic circulation over the southeast and the east-central Arabian Sea, along with a persisting trough running through Gujarat’s Kutch region at mean sea level (MSL), which are bringing moisture-laden winds over the city. Rains in December are rare for Mumbai but do occur with much less intensity. On December 11, 2020, the city recorded 0.7mm of rain due to a similar cyclonic circulation in the Arabian Sea. On December 5, 2019, due to similar meteorological conditions, the city had received 1.2mm of rain.
An official with the IMD’S regional forecasting centre in Mumbai informed, “A prolonged spell of rain like we are seeing is extremely unlikely in December. In terms of the synoptic features, we know what is causing it, but we will have to wait much longer to see if there is any change in rainfall trends. It is also unlikely for such rains to happen again this month,” said an official with the IMD’S regional forecasting centre in Mumbai. These rains, which will continue with reduced intensity on December 3, resulted in a steep dip in temperature, added IMD official.