The maritime ports of Chattogram, Cox's Bazar, Mongla and Payra have been advised 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 East Central Bay and the adjoining North Bay.
It is likely to intensify further, said a special bulletin of the Met office on Thursday morning.
Under its influence, deep convection is taking place over the North Bay and its adjoining areas. Squally weather may affect the maritime ports, the North Bay and the adjoining coastal areas of Bangladesh, it added.
All fishing boats and trawlers over the North Bay have been advised to come closer to the coast and proceed with caution until further notice. They have been also advised not to venture into the deep sea.
Deep convection refers to the thermally driven turbulent mixing that moves air parcels from the lower to the upper atmosphere.