Oscar is still moving toward the west at 16 miles per hour.
Forecasters expect Oscar to become a hurricane later Sunday as its track curves toward the North Atlantic.
Oscar became a tropical storm Saturday and was designated the eighth hurricane this season in the 5 p.m. advisory.
There were no coastal watches or warnings in effect. This storm is about 730 miles southeast of Bermuda with sustained winds of 75 mph.
"Environmental conditions appear conducive for further development and this system will likely become a tropical or subtropical cyclone later today or tonight while it moves generally northward over the central Atlantic".
Lion Air flight from Jakarta to Sumatra crashes, rescue agency says
The Lion Air flight took off for the 50 minute journey to the Banka island across the Natuna Sea off South Sumatra, at 6:20 a.m. Lion Air told reporters it was still trying to gather all the relevant data and would hold a press conference later on Monday.
Forecasters said Oscar was developing a warmer core, indicating it would transition soon to a tropical storm. Storms become hurricanes at 74 miles per hour.
The 2018 Atlantic hurricane season officially started June 1, and it will end on November 30, the NHC said.
Tropical Storm Oscar continues to swirl over the Atlantic Ocean, but it does not pose any threat to land.
Thirty-five people have died in Florida and 10 died in other states.