After a brief lull, the Bay of Bengal arm of the south-west monsoon has stirred into action and entered north-eastern parts of the country and is set to bring heavy rains over Assam and Meghalaya over the next two days, the IMD said Thursday. "Southwest monsoon has further advanced into some parts of northwest Bay of Bengal, some more parts of northeast & east-central Bay of Bengal and most parts of Mizoram, Manipur, and Nagaland," the India Meteorological Department said.