Mumbai: At 253 mm, the India Meteorological Department’s (IMD) Santa Cruz Observatory recorded the second highest 24-hour rainfall for July between July 15 and 16 (8.30 am to 8.30 am). Earlier, between July 1 and 2, 2019, the Santa Cruz Observatory had reported 375.2 mm of rainfall, the highest single-day rainfall ever recorded in the past ten years. As per the classification of IMD, the rainfall recorded by the Santa Cruz Observatory falls in the extremely heavy category.
However, no warning of extremely heavy rain was issued, and experts said this was because it was a local phenomenon, with rain confined only to the northern suburbs of Mumbai. Colaba observatory recorded 12.8 mm of rain. After overnight and morning rains, the IMD, which had also given a yellow alert for Mumbai for July 16, continued to upgrade it to orange, indicating heavy to very heavy rainfall at isolated places. .
Dr. Jayant Sarkar, Scientist and Head, IMD MumbaiGiving the forecast for the next five days, it said, “For Friday we have given Orange Alert (Heavy to Very Heavy Rain) while for Saturday, a Yellow Alert has been issued for Mumbai.” Rainfall data showed that the rains had started at 2.30 am on Friday, with the maximum rainfall recorded between 5.30 am and 8.30 am in excess of 150 mm.
With heavy overnight rains, the month of July has recorded 583 mm of rain so far, which is 70% of the average monthly rainfall i.e. 827.5 mm. Meanwhile, the total rainfall recorded so far for the season is also 70% of the July average rainfall. In the 12 hours ended at 8.30 pm on Friday, however, the IMD Santa Cruz observatory recorded 15.7 mm of rain and Colaba observatory 4.8 mm of light rain.
Officials of private forecasting agency Skymet attributed the heavy rains to the fact that the monsoon surge was very strong. “The weather is not likely to be completely dry even though the growth will weaken over the weekend. Although such heavy rain of 253 mm was not expected, but the situation has turned favorable for it. We expect the next heavy round to occur around July 21, with a low pressure area likely to form over northwest Bay of Bengal and adjoining areas during that period.
Some experts said the current operational weather models would not be able to predict such an event.
Akshay Deoras, an independent meteorologist who is a PhD student at the Department of Meteorology, University of Reading, UK, said the current large-scale weather conditions were not conducive for heavy, widespread and sustained rainfall. He said a strong thunderstorm hit the suburbs early in the morning and as it matured, easterly winds pushed it away from the city, resulting in very little rain in Colaba and south Mumbai, he said. “Such storms are more common in June before the monsoon arrives. Several factors may be responsible for the formation of thunderstorms only in the suburbs, but the role of mountains (in suburban areas, i.e. Sanjay Gandhi National Park) cannot be ruled out. While weather models can predict large-scale precipitation events well, they have limitations in simulating such local and transient rainfall events,” Deoras said.
However, no warning of extremely heavy rain was issued, and experts said this was because it was a local phenomenon, with rain confined only to the northern suburbs of Mumbai. Colaba observatory recorded 12.8 mm of rain. After overnight and morning rains, the IMD, which had also given a yellow alert for Mumbai for July 16, continued to upgrade it to orange, indicating heavy to very heavy rainfall at isolated places. .
Dr. Jayant Sarkar, Scientist and Head, IMD MumbaiGiving the forecast for the next five days, it said, “For Friday we have given Orange Alert (Heavy to Very Heavy Rain) while for Saturday, a Yellow Alert has been issued for Mumbai.” Rainfall data showed that the rains had started at 2.30 am on Friday, with the maximum rainfall recorded between 5.30 am and 8.30 am in excess of 150 mm.
With heavy overnight rains, the month of July has recorded 583 mm of rain so far, which is 70% of the average monthly rainfall i.e. 827.5 mm. Meanwhile, the total rainfall recorded so far for the season is also 70% of the July average rainfall. In the 12 hours ended at 8.30 pm on Friday, however, the IMD Santa Cruz observatory recorded 15.7 mm of rain and Colaba observatory 4.8 mm of light rain.
Officials of private forecasting agency Skymet attributed the heavy rains to the fact that the monsoon surge was very strong. “The weather is not likely to be completely dry even though the growth will weaken over the weekend. Although such heavy rain of 253 mm was not expected, but the situation has turned favorable for it. We expect the next heavy round to occur around July 21, with a low pressure area likely to form over northwest Bay of Bengal and adjoining areas during that period.
Some experts said the current operational weather models would not be able to predict such an event.
Akshay Deoras, an independent meteorologist who is a PhD student at the Department of Meteorology, University of Reading, UK, said the current large-scale weather conditions were not conducive for heavy, widespread and sustained rainfall. He said a strong thunderstorm hit the suburbs early in the morning and as it matured, easterly winds pushed it away from the city, resulting in very little rain in Colaba and south Mumbai, he said. “Such storms are more common in June before the monsoon arrives. Several factors may be responsible for the formation of thunderstorms only in the suburbs, but the role of mountains (in suburban areas, i.e. Sanjay Gandhi National Park) cannot be ruled out. While weather models can predict large-scale precipitation events well, they have limitations in simulating such local and transient rainfall events,” Deoras said.
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