The maritime ports of Chattogram, Cox's Bazar, Mongla and Payra have been directed to keep hoisted local cautionary signal 3.
A depression over Northwest Bay and adjoining Odisha coast intensified further into a deep depression and moved West-Northwestwards, said a Met office bulletin on Monday.
It is likely to move in a west-northwesterly direction further, it said.
Squally weather may affect the maritime ports, North Bay and adjoining coastal areas of Bangladesh.
The Met office advised all fishing boats and trawlers over North Bay to remain close to the coast and proceed with caution until further notice.
They were also advised not to venture into the deep sea.
Besides, the low-lying coastal areas of Bagerhat, Khulna, Satkhira, Chattogram, Jhalakathi, Bhola, Barishal, Patuakhali, Barguna, Bhola, and Laximpur are likely to be inundated by a wind-driven surge of 2-3 feet above the normal astronomical tide.
