A low-pressure belt over coastal Odisha is tipped to keep Sunday wet for Calcutta.

The sky will remain overcast till Tuesday and light to moderate rain is expected over the next two days, the Met office has said.

A cyclonic circulation formed over Northwest Bay of Bengal a couple of days ago. The circulation intensified into a low-pressure belt and was over coastal Odisha and neighbouring Bay of Bengal on Saturday.

“The system extends up to 7.6km from the sea level and is tilted westwards. It is expected to cause heavy rain in Odisha and in some places in the western districts of Bengal,” G.K. Das, director, India Meteorological Department, Calcutta, said. “Calcutta is expected to get light to moderate rain over the next 48 hours. There could be multiple spells but not heavy rain.”

Some areas in West Midnapore, Jhargram, Bankura and Purulia might get heavy rain, he said.

Odisha has already sounded an alert because of the low-pressure belt, asking the coastal district administrations to be prepared. Fire services, state disaster rapid action force and the National Disaster Response Force have been asked to remain in a state of readiness for deployment for search and rescue operations, if needed, according to a PTI report.

The sky in Calcutta has remained overcast since Friday with occasional showers since Thursday evening. The maximum temperature remained consistently more than 33 degrees Celsius from Monday to Friday. On Wednesday, it was 35.1 degrees Celsius, three notches above normal. On Saturday, it was 29.2 degrees, three notches below normal.

In the past 24 hours, Dhapa and adjacent areas got 40mm of rain, Dum Dum 31mm and Ballygunge 30mm, according to a weather-tracking website of Calcutta Municipal Corporation.

On Saturday afternoon, the sky was fairly dark and some areas received some rain.

“A system in the Northwest Bay and adjoining Odisha coast leads to more rain in the western districts of Bengal. A system over Bangladesh and neighbouring Bay of Bengal leads to more rain in Calcutta and the two Parganas,” Das said.

In July and in the first half of August, most rain-triggering systems formed in the Northwest Bay and coastal Odisha, leading to scarce rain in Calcutta. But in the run-up to Independence Day, a system over Bangladesh led to heavy rain in Calcutta and reduced the monsoon deficit.

August has so far seen more than 480mm of rain in Calcutta. The normal count is 344mm, a Met official said.