A low-pressure area is likely to be formed over the South Andaman Sea by the end of this week, the weather office said on Tuesday.
In its tropical weather outlook, the weather office said that a cyclonic circulation is likely to form over South Andaman Sea and its adjoining areas around May 4.
Under its influence, a low-pressure area is likely over the region around May 6.
"Probability of cyclogenesis during next 120 hours high," the weather office said, even as it refrained from making any forecast on the path of the low-pressure system.
"It is likely to become more marked during subsequent 24 hours," it said.
In its warning for fishermen for May 4, it said squally wind is very likely to prevail over South Andaman Sea and adjoining southeast Bay of Bengal.