The districts of Purba and Paschim Bardhaman, Birbhum, Nadia, Murshidabad, North and South 24 Parganas are likely to experience heavy rainfall till Thursday, it said. Heavy rain is also expected in the sub-Himalayan districts of Darjeeling, Kalimpong, Jalpaiguri, Alipurduar and Cooch Behar, owing to the monsoon flow, the bulletin said.