A cyclonic circulation, which took shape over the Bay of Bengal on Monday, is poised to trigger another spell of heavy rain in Kolkata over the next 48 hours.
If the Met forecast comes true, this will be the second spell of heavy rain in the city in two successive weeks. Many parts of Kolkata and adjoining areas received torrential rain — over 200mm in 36 hours, starting from the night of the Sunday before last (September 19) — during the previous spell.
“A cyclonic circulation lies over east-central and adjoining northeast Bay of Bengal, off Myanmar coast, extending up to mid-tropospheric levels. It is likely to move towards the Bengal coast. Enhanced rainfall activity is likely over the districts of south Bengal during September 28 and 29,” said a bulletin from the Indian Meteorological Department, Kolkata.
Under the influence of the system, heavy rain is likely in Kolkata, Howrah, Hooghly, North and South 24-Parganas and East and West Midnapore districts on Tuesday and Wednesday, said a Met official.
The system will head towards the western districts of Bengal after hitting land. On Wednesday, in addition to the earlier mentioned places, Bankura, Jhargram and Purulia are also likely to get heavy rain.
“The system is likely to generate winds blowing at 60kmph in the coastal areas as it nears land towards the evening. Kolkata is likely to see winds blowing at 50kmph,” said the official.
The impact on Kolkata will also depend on the path of the system after entering land. If it passes right over the city, the impact will be more. “As of now, the system is tipped to skirt Kolkata but not by much,” said the official.
The rivers, canals and ponds are already overflowing in south Bengal because of the surge in rainfall at the fag end of the monsoon. Any fresh downpour is likely to cause more flooding, even in urban areas.
The conditions in Kolkata are likely to be overcast from Tuesday morning. “Multiple spells of rain are expected throughout the day. But heavy rain is more likely in the late evening or night,” said G.K. Das, director, IMD, Kolkata.
“The sea breeze blowing through the day is expected to push the rain-bearing clouds towards the land. After a sufficient build-up of clouds, a spell of heavy rain is likely in the evening or night,” he said.
During the previous downpour, between Sunday night and Monday morning, the city had received around 150mm of rain.
The Met office had earlier predicted that the cyclonic circulation would intensify into a low-pressure area.
“There is a chance that the system may not intensify and continue being a cyclonic circulation when it touches land. But it will still be potent enough to cause heavy rain,” said Das.