Low-lying areas in coastal districts are likely to be inundated by tidal surges, according to a bulletin the Met office.
The districts are Chattogram, Noakhali, Laxmipur, Feni, Chandpur, Barguna, Bhola, Patuakhali, Barishal, Pirojpur, Jhalokathi, Bagerhat, Khulna, Satkhira and their offshore Islands and chars incluidng Hatiya, Sandwip.
Due the influence of new moon phase and deep depression in the Bay of Bengal, the low-lying areas of the these districts are likely to be inundated by wind driven surge of 2-4 feet height above normal astronomical tide, it said.
Met office warns of cyclonic storm as Bay depression intensifies
The deep depression over the Northwest Bay and adjoining area moves further northwards and starts crossing the West Bengal-Bangladesh coast between Sagar Island and Khepupara, said the bulletin.
It may move nearly northwards further and complete crossing the coast by Thursday evening and weaken gradually, said the latest bulletin of the Met office.
Under its influence, gusty or 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 centre is about 50 kph rising to 60 kph in gusts or squalls.
Sea will remain moderate near the deep depression centre.
Maritime ports of Chattogram, Cox's Bazar, Mongla and Payra have been advised to keep hoisted local cautionary signal no three.
All fishing boats and trawlers over North Bay have been advised to remain in shelter till further notice.