india

Updated: Sep 25, 2019 12:56 IST

Continuous lightning flashes accompanied by loud echoes of thunder with sporadic intense rain spells were witnessed between Tuesday night and Wednesday morning in the city and suburbs.

South Mumbai recorded heavy showers with 67.2 mm between 11.30pm Tuesday and 8.30am Wednesday (27 mm rain was recorded over three hours – 5.30am to 8.30am Wednesday) while moderate rain was recorded in the suburbs at 30.2 mm during the same time. While 15.6mm to 64.4mm of rain is considered ‘moderate’, 64.5mm to 115.5mm ‘heavy’.

Over the past 24 hours (8.30am Tuesday and 8.30am Wednesday), Matheran recorded the highest rain in the state at 108.4 mm, followed by Beed at 98 mm, Ratnagiri 98.9 mm, Kolhapur 64.2mm and Mahabaleshwar 53 mm.

Intense thundershowers were recorded in the city against the India Meteorological Department’s (IMD) forecast for light to moderate showers for Wednesday. The weather bureau said similar intermittent rain spells with isolated heavy showers are likely to continue through the day on Wednesday and Thursday with intense thundershowers overnight again.

“Widespread convective activity with rumbling thunder was witnessed across Mumbai, Thane, and Navi Mumbai overnight with a major rain spell over three hours on Wednesday morning owing to strong gusty westerly winds drawing moisture from the sea to land as result of surface heating during the day on Tuesday,” said KS Hosalikar, deputy director-general, western region, IMD.

Independent meteorologists over the weekend had issued the correct forecast for such rain spells for Wednesday and Thursday.

“A weak upper air cyclonic circulation over the Arabian Sea towards the Mumbai coast will lead to thundershowers during the evening and late-night owing to distinctive weather conditions (strong convergence),” said Sridhar Balasubramanian, associate professor, department of mechanical engineering and associate faculty, IDP Climate Studies, IIT- B.

Other weather experts said these thundershowers in the MMR and other parts of Maharashtra is among the final rainfall events of this year’s monsoon season. “There will be a sharp decline in the rain activity from early October. Monsoon’s withdrawal is expected to initiate in Maharashtra from the second week of October,” said Akshay Deoras, meteorologist and PhD researcher, University of Reading, UK. “Increase in moisture over Mumbai is leading post-noon thundershowers. Compared to the city and suburbs, eastern outskirts of MMR (Matheran and surrounding areas) are likely to witness more rainfall activity. This rainfall activity is due to a low-pressure circulation near south Konkan and has no connection with the tropical cyclone Hikka (moving closer to Oman).”

Mumbai has so far recorded 3,634.3 mm rain, which is one of the highest seasonal rainfall recorded since records are being maintained by IMD, and is currently 70% in excess of normal rain for the season with another five days still to go till the end of the month and four-month southwest monsoon.