A fresh system is likely to trigger more rain in Calcutta from Wednesday.

“An upper air cyclonic circulation lies over north Bangladesh and neighbourhood. It is likely to descend in a day or two. A fresh rainy spell is likely in south Bengal, including Calcutta,” said a Met official on Tuesday.

The monsoon trough now passes through Punjab, Uttar Pradesh, Bihar and then east-northeastwards to Arunachal Pradesh close to the foothills of the Himalayas. Under its influence, north Bengal is likely to continue getting heavy rain, according to the forecast.

In south Bengal, North and South 24-Parganas, Howrah and Nadia are likely to get heavy rain on Wednesday. Birbhum, Murshidabad, East and West Burdwan, Bankura, West Midnapore and South 24-Parganas are likely to get heavy rain on Thursday.

Moderate showers, accompanied by lightning and wind, are expected across south Bengal. “In Calcutta, the intensity of the showers is likely to go up on Thursday,” said the Met official.