Dhaka, April 29 -- A steep pressure gradient is persisting over the North Bay of Bengal and adjacent areas, leading the Bangladesh Meteorological Department (BMD) to instruct the country's four maritime ports to maintain the cautionary signal No. 3.

In a special warning issued by the Meteorological Department on Wednesday, the seaports at Chattogram, Cox's Bazar, Mongla and Payra have been asked to keep the cautionary signal hoisted.

Along with this, fishing boats and trawlers in the North Bay have been asked to stay close to the coast and proceed with caution until further notice.

The BMD's regular bulletin on Wednesday morning said light to moderate rain or thundershowers accompanied by gusty or squally winds and lightning are likely...