The Mumbai Metropolitan Region (MMR) received intermittent spells of intense showers through Thursday morning — four days after the onset of the south-west monsoon in the city and its suburbs.
The suburbs recorded 19.4 millimetres (mm) of rainfall between 8.30am and 2.30pm, south Mumbai (8.4 mm) and Thane (40 mm).
A location-wise rainfall over the six hours showed most parts of the eastern suburbs recorded maximum rain ranging between 35 and 40 mm.
While in the north-western suburbs, starting from Andheri to Borivali and Dahisar, received 30-35 mm and Dadar, Byculla, Worli, and Mahalaxmi recorded 32-40 mm.
The weather bureau issued a Nowcast warning at 11.45am on Thursday for intense spells of heavy rain for the afternoon.
“An upper air cyclonic circulation over the north Konkan and the neighbourhood between 3.1 kilometres (km) to 7.6km intensified monsoon currents and westerly wind pattern over the Mumbai region will lead to intense rain, especially towards the suburbs accompanied with thunder,” said KS Hosalikar, deputy director-general, western region, India Meteorological Department (IMD).
“Satellite and radar images have indicated clouds at a height of seven to eight km over the city, which will lead to more intense showers throughout the day. The 24-hour forecast indicates heavy rain for MMR, while very heavy rain at isolated places in the south Konkan region,” he added.
Earlier, the weather bureau had issued an orange alert (heavy to very heavy rain) for Monday to Wednesday.
However, on Wednesday, IMD had downgraded its forecast for Thursday to “light to moderate” rain.
But, once the Nowcast warning was issued and intense showers were recorded over the city, the forecast was changed to a yellow alert (heavy rain) at 1pm.
Light to moderate rain forecast has been issued for Friday and the weekend.
Independent meteorologists explained the wind pattern over Mumbai on Thursday has changed, as compared to previous days allowing monsoon winds to push rain clouds over the city.
“Under the influence of a low-pressure circulation over the northern Arabian Sea, the offshore trough (weather system) is active and is triggering the formation of clouds. In addition, there has been localised development of clouds over Mumbai on Thursday,” said Akshay Deoras, independent meteorologist and a PhD researcher at the University of Reading, the United Kingdom (UK).
“The offshore trough will weaken from Friday, leading to a sharp reduction in rainfall during the weekend and only intermittent showers are expected,” he added.
Mumbai and its suburbs can expect intermittent rain with heavy showers likely in isolated areas over the next 24 hours, and moderate rain over 48 hours.
Maximum rains were recorded in south Konkan districts with 137 mm rain in cyclone Nisarga-hit Shrivardhan taluka of Raigad district, Ratnagiri (122) mm, Harnai (94.2 mm), and Mahabaleshwar (74.7 mm) over the past 24 hours.