August so far has registered a rain deficit of over 40 per cent in Kolkata, despite starting on a rainy note.
Between August 1 and 24, the city received around 155mm of rain, compared to its quota of 273mm for the period, according to the Met office in Alipore.
“There is little chance of any fresh rain-bearing system taking shape over the Bay of Bengal. In all likelihood, the month will end with a shortfall. A strong spell of thunderstorm, triggered by the formation of local clouds because of the pent-up heat can reduce the deficit,” an official said.
August’s usual quota is around 340mm of rain in the city, he added.
The shortfall was attributed to the absence of low-pressure areas or cyclonic circulations over the Bay.
The city received heavy rain in the first week of August because of a cyclonic circulation over the north Bay of Bengal. After that, there has been no system over the Bay to bring rain to Kolkata and south Bengal.
“July and August are the two rainiest months of monsoon. They are known for the formation of frequent systems over the Bay. July had multiple such systems. But August has not seen more than one. A system closer to Bangladesh usually has more impact on Kolkata. But even a system over northwest Bay, closer to the Odisha coast, has some impact. But the lack of any has meant not much rain,” said GK Das, the director of IMD, Kolkata.
The monsoon trough has for long stayed at the foothills of the Himalayas, leading to consistent rain in north Bengal for most of August.
“A low-pressure area along the Andhra Pradesh coast is tipped to bring the trough down after August 27 but the system will be far enough from Kolkata to have any substantial impact.
The weather in Kolkata has remained hot and sweaty for the past few days. There is no respite in the next few days, said the Met official.
The only hope is one or two strong spells of thunderstorms, triggered by local clouds formed from the high moisture content and pent-up heat.
Similar spells came down on pockets of Kolkata and its surrounding areas in the run-up to Independence Day.
But in between the showers, the weather is likely to be uncomfortable, said the official.
