Cyclonic Storm Arnab is likely to intensify into a severe cyclonic storm over the west-central Bay of Bengal by Monday midnight, Bangladesh Meteorological Department (BMD) said.

The deep depression over the east-central Bay of Bengal and adjoining south-east Bay moved north-westwards and intensified into Cyclonic Storm Arnab, said a special weather bulletin of the BMD on Monday morning.

At 6:00am on Monday, the storm was centred over the east-central Bay and adjoining west-central Bay, near latitude 15.4°N and longitude 89.0°E.

It was about 820km south-west of Chattogram, 745km south-west of Cox's Bazar, 785km south of Mongla and 745km south of Payra, the bulletin said.

The storm is likely to move west-north-westwards and intensify into a severe cyclonic storm over the west-central Bay by midnight and expected to move north-westwards and cross the Andhra Pradesh coast by October 28 as a very severe cyclonic storm, it added.

The maximum sustained wind speed near the storm's centre is about 62 kilometres per hour, rising to 88kmph in gusts or squalls. The sea is likely to remain very rough near the centre of the storm.

The BMD has advised the maritime ports of Chattogram, Cox's Bazar, Mongla and Payra to hoist distant warning signal No. 2 (R) instead of warning signal No. 1.

All fishing boats and trawlers operating in the North Bay have been advised to remain close to the coast and proceed with caution until further notice, the bulletin added.