A fresh cyclonic circulation over the Bay of Bengal triggered a sharp spell of rain in Calcutta on Monday night and early on Tuesday.

The system is likely to bring more rain to Calcutta over the next three days, the Met office has said.

Between 8.30pm on Monday and 8.30am on Tuesday, the Met office recorded around 40mm of rain in Alipore. The Met observatory in Salt Lake recorded over 70mm of rain during the same period.

In Met parlance, 60mm or more rain in 24 hours qualifies as heavy.

Monday was exceptionally humid and sweaty and the rain brought some relief the next morning. The relief was short-lived and as the sun came out, the weather became sweaty again.

“The cyclonic circulation is over the north Bay of Bengal. It is unlikely to intensify into a low-pressure area. But the system will lead to a wet spell over south Bengal over the next three days,” said a Met official.

“Coastal districts of South and North 24-Parganas, Howrah and Hooghly can get a spell or two of heavy rain because of the system. Calcutta is likely to get moderate rain,” the official said.

The next few days are also likely to be sweaty. The sun will be out when it is not raining. The intervals between the showers are likely to be uncomfortable, said the Met official.