Kolkata: A stationary low-pressure area over Gangetic Bengal and the adjoining regions triggered a relentless downpour on Tuesday, with Alipore Met office recording 93.6 mm till 11:30 am. Along with the low-pressure area that has refused to move away, meteorologists attributed the deluge to strong low-level southerly winds pushing massive moisture convergence from the Bay.The 93.6 mm (around 73.4 mm of rain since Tuesday morning) rain is likely to be the highest 24-hour rain count the city has encountered this monsoon. While the downpour left parts of the city under water, the Met officials said the worst is over and the rain frequency and intensity are expected to start reducing from Wednesday.“The low-pressure area has not moved away as expected. Also, strong southerly wind in the lower level over south Bengal is causing moisture convergence which is fueling the formation of more cloud,” said Met scientist HR Biswas, head at Regional Meteorological Centre (RMC), Kolkata.The well-marked low-pressure area that persisted over Gangetic Bengal and adjoining areas of north coastal Odisha and northwest Bay of Bengal on Monday was expected to move west-northwestwards across north Odisha and Gangetic Bengal by Tuesday morning. But the system refused to move away, causing the incessant rain in Kolkata and in other districts, including Howrah, North and South 24 Parganas, Hooghly, East and West Burdwan, Birbhum, Bankura and Purulia.According to available data, the 24-hour highest rain count in June, July and Aug stands at around 88.6 mm, 50.4 mm and 90 mm, respectively.Sept is counted as the third rainiest monsoon month for Kolkata and the rest of south Bengal. Under normal circumstances, Kolkata should get a monthly rain count of 311 mm by the month-end. The city has received more than one-third of the monthly rain on the first day itself.According to a special IMD bulletin, the low-pressure area is likely to move west-northwestwards across north Odisha and Jharkhand in the next 48 hours, while the rainfall activities in south Bengal are expected to reduce from Wednesday, they will pick up pace in north Bengal.
