As of 4 p.m. ET Wednesday, the center of Subtropical Storm Alex was located about 785 miles south-southwest of the Azores, a small island chain about 850 miles from Portugal. It had maximum sustained winds of 50 mph.
A subtropical storm contains meteorological characteristics of both tropical and non-tropical storms.
The hurricane center warned gale force winds should hit the Azores by late Thursday or early Friday. Heavy rain could also lead to life-threatening flash floods and mudslides.
Alex is the first tropical or subtropical storm to form in January since an unnamed system in 1978, according to Rick Knabb, director of the hurricane center.