Maritime ports of Chattogram, Cox's Bazar, Mongla and Payra have been advised to keep local cautionary signal number 3 hoisted as the depression over the west-central Bay and adjoining area moved northeast and intensified into a deep depression.
It was centred at 6 am on Thursday about 785 km southwest of Chattogram port, 745 km southwest of Cox's Bazar port, 655 km southwest of Mongla port and 655 km southwest of Payra port, said a Met office bulletin.
It is likely to intensify and move northeastward further.
Under its influence, deep convection is taking place over North Bay.
Squally weather may affect the maritime ports, North Bay and adjoining coastal areas of Bangladesh.
Maximum sustained wind speed within 48 km of the deep depression center is about 50 kph rising to 60 kph in gusts or squalls.
The sea will remain moderate near the deep depression centre.
All fishing boats and trawlers in North Bay and Deep Sea have been advised to remain close to the coast and proceed with caution till further notice. They are also advised not to venture into the deep sea.