Michael, with maximum sustained winds of 75 mph, was about 1,175 miles west of the Azores moving west at 12 mph, the National Hurricane Center in Miami said in its 5 p.m. EDT forecast.
No watches or warnings were posted.
Michael had turned northwestward and was expected to shift northward or northeastward and gather some speed Tuesday, the center said.
Forecasters said Michael could weaken from a Category 1 hurricane by Monday night.
Hurricane force winds extend from Michael's center outward to about 25 miles, the center said. Tropical storm winds extend outward from center about 80 miles.