A forecast for heavy rain looms over Calcutta on Dashami with a system over the Bay of Bengal turning into a depression on Wednesday and threatening to intensify into a deep depression by Thursday.
In Met parlance, heavy rain means between 70mm and 110mm (7cm and 11cm) in 24 hours.
“The well-marked low-pressure area over the west-central Bay of Bengal moved north-northwestwards and concentrated into a depression,” said an official of the Met office in Alipore.
It is very likely to continue to move north-northwestwards, intensify further into a deep depression and cross the Odisha and adjoining Andhra Pradesh coasts between Gopalpur and Paradip early Friday morning.
“A deep depression is a more powerful system than a depression, and its ability to bring rain is greater,” said the Met official.
Under its impact, large parts of south Bengal are likely to receive heavy to very heavy rain.
A special bulletin issued by the India Meteorological Department (IMD) said “heavy rain (7-11cm)” was “very likely to occur at one or two places” in Calcutta.
Some pockets of neighbouring Howrah, North 24-Parganas and Hooghly might also receive heavy rain.
Heavy to very heavy rain is likely at one or two places over South 24-Parganas.
Heavy to very heavy rain has also been forecast for other south Bengal districts.
The Met office also forecast accompanying thunderstorms with gusts of wind reaching up to 50kmph and lightning over East and West Midnapore and South 24-Parganas.
Other south Bengal districts may experience thunderstorms with gusts of wind going up to 40kmph.
The bright and sunny sky of Wednesday morning changed into a dark, menacing grey on Navami afternoon. There were mild showers here and there, not the type of rain that revellers mind.
A visitor outside the Hindusthan Park pandal in south Calcutta said she was worried that the rain would cut her day short.
“Luckily, it did not rain that much. I visited Tridhara Sammilani, Ballygunge Cultural Association and Chetla Agrani,” she said.
A Kolkata Police officer said parts of south Calcutta experienced low-intensity
rain for 15 minutes around 3.30pm. The rain stopped thereafter. “But the crowd was thinner on Wednesday evening than on Tuesday or Monday,” said the assistant
commissioner.
The rain was sharper in pockets of north Calcutta.
An organiser of Tala Prattoy said a spell of intense rain occurred for some time around 3.30pm. Although the intensity reduced, a drizzle continued for much of the evening.
People still came to the Puja in large numbers, he said.
“People are still coming to our pandal despite the rain. We are also keeping an
eye on the weather forecast. The puja is held on a ground, so we have kept six pumps ready so that we can drain out the water if there is waterlogging,” said Dhrubajyoti Bose Suvo, one of the organisers.