Nadine, with maximum sustained winds of 50 mph throughout the day, was about 445 miles south-southwest of the Azores, moving west at 7 mph, the National Hurricane Center in Miami said in its 5 p.m. EDT advisory.
No coastal watches or warnings were in effect.
Forecasters said Nadine wasn't expected to change in intensity much during the next two days.
Tropical storm-force winds extended outward up to 185 miles from the storm's center.
Nadine was expected to turn to the west-southwest and slow down Tuesday, then veer to the south Tuesday night.