The maritime ports of Chattogram, Cox’s Bazar, Mongla and Payra have been asked to hoist at the mast local cautionary signal No 3 to alert vessels of a possible squall. The weather office's advisory for cautionary signal No 3 -- which means a depression has formed and may affect the port later -- comes in the wake of the formation of a low pressure area over the west-central Bay and the adjoining Northwest Bay. It is likely to intensify further, the  Bangladesh Meteorological Department (BMD) said in a special bulletin on Saturday morning. Under its influence, a deep convection is taking place over the North Bay and adjoining areas. Squally weather may affect the maritime ports, the North Bay and the adjoining coastal areas of Bangladesh. Read: Low pressure likely over North Bay in 72 hrs: Met office All fishing boats and trawlers over the North Bay and deep sea have been advised to remain closer to the coast and proceed with caution till further notice, the bulletin said. They have also been advised not to venture into the deep sea.