It is likely to intensify further and move in a north-northwesterly direction, the Bangladesh Meteorological Department warned in a special bulletin on Thursday night.
It was situated around 700 to 800 kilometres off the maritime ports at midnight.
Gusty or squally wind may affect the maritime ports, North Bay and coastal areas under the peripheral influence of the storm, the Met Office said.
The sea will remain very rough near the centre of the storm with maximum sustained wind speed of up to 110 kilometres per hour.
The Met Office raised the warning level at the maritime ports to Local Cautionary Signal No. 3 from 2.
All fishing boats and trawlers over North Bay have been advised to take shelter immediately and remain in shelter till further notice.
It is likely to reach the North Bay on Sunday, he said.
“The coastal areas are likely to experience light rains as water vapour level has risen due to the storm,” he added.
Meteorologists said rains are also likely in India’s Odisha and West Bengal coasts under the influence of the storm.
They could not confirm its pathway yet.
The Indian Meteorological Office said it is likely to turn into a Very Severe Cyclonic Storm by Friday afternoon with maximum sustained wind speed of 145kmph. It will weaken and may become a Severe Cyclonic Storm on Sunday before turning into a Cyclonic Storm on Monday.
The Joint Typhoon Warning Centre said the storm may enter Bangladesh on Sunday morning.
Abdul Mannan said the Bangladesh Met Office will raise the warning signal further after watching the situation on Saturday night as they are not certain about its possible pathway.