Mumbai Hit By Heaviest Rains Since 2019 Brings City To Standstill | Record Breaking Rainfall!

In what was the city's highest one-day rainfall since 2019, a torrential downpour brought Mumbai to a standstill on Monday morning, with several areas receiving over 300 mm of rain in just a few hours. The Indian Meteorological Department's (IMD) suburban station recorded 268 mm of rain in the past 24 hours ending Monday morning, with 210 mm falling within just two hours, as reported by Indian Express.

The IMD attributed the intense rainfall to the strengthening of an offshore trough around midnight. This unexpected deluge, which most weather models failed to predict, left many meteorologists puzzled. Heavy showers lashed Mumbai between Sunday night and Monday morning, with the Brihanmumbai Municipal Corporation (BMC) reporting the heaviest rainfall in the eastern suburbs.

The Automatic Weather System (AWS) recorded 315.6 mm of rain in Vikhroli, 314.5 mm in Powai, 292 mm in Andheri East, 272 mm in Chakala, and 259 mm in Aarey. IMD data showed that the Santacruz recording station registered 268 mm of rain, while the Colaba center recorded only 84 mm between Sunday and Monday morning.

This marked the highest 24-hour rainfall since July 2, 2019, when the suburbs recorded 375.2 mm. According to IMD scientist Sushma Nair, a nowcast warning was issued around midnight, but the rain intensified significantly after 2:30 am. "Our records show that the Santacruz station registered only 40.9 mm of rain until 2:30 am, as reported by Indian Express.

After that, 210.9 mm was recorded between 2:30 am and 4 am," said Nair. The heavy showers were attributed to the strengthening of an offshore trough along the north Gujarat and Kerala coasts, which intensified along the north Konkan coast around midnight.

Despite a yellow warning issued by the IMD on Sunday, indicating the likelihood of 'heavy rainfall at isolated places,' no warning was issued for Monday or the rest of the week. This failure to flag the extreme weather event drew criticism from citizens, who faced an inundated city throughout Monday.

An IMD official explained that the overnight weather event was likely caused by an offshore vortex. "Our models could not capture such an intense yet small-scale weather system and the resulting rains," said the official, as per media reports. Weather experts across the city noted that all models, including those of the IMD, failed to predict the extremely heavy rainfall.

Subimal Ghosh, an IIT-Bombay professor and convener of the interdisciplinary program in climate studies, stated, "None of the models could forecast the extreme rains. The IMD model placed no warnings. The ECMWF model forecast low rainfall. Even the NCEP-GFS model showed low rainfall." Ghosh added, "We are yet to determine what caused the extreme rain event in Mumbai. We are now trying to understand the factors by looking at the circulation, moisture flow, wind directions, etc."

Raghu Murtugudde, a professor of climate studies at IIT-Bombay, attributed the heavy showers to the northward expansion of the southwesterly jet, which forecast models often fail to capture. "Mumbai has been at the edge of the southwesterly jet for weeks, resulting in a rain deficit. But yesterday, this jet expanded slightly northward and started pumping moisture directly, causing heavy rains," said Murtugudde, as reported.

After the overnight downpour, heavy showers continued to batter the city. While rain activity in the suburbs diminished, the island city division recorded over 100 mm of rain in nine hours on Monday. IMD data showed that the Santacruz observatory recorded 14.1 mm between 8:30 am and 5:30 pm, while the Colaba coastal observatory recorded 101.8 mm during the same period, as per media reports.

In light of the continued downpour, the IMD issued a red alert for Mumbai until Tuesday morning, indicating that heavy to very heavy rainfall would continue. "We have received over 100 mm of rain in the past few hours and are expecting over 100 mm more in the next 12 hours. Therefore, a red alert has been issued," said Sunil Kamble, director of IMD Mumbai.