Earlier a tropical storm, Sam has strengthened into a hurricane and is expected to continue intensifying, the National Hurricane Center said Friday.

The storm is the seventh hurricane of the 2021 Atlantic season, with winds of 75 mph and even higher gusts, according to an NHC update Friday morning. Sam is forecast to become a major hurricane -- Category 3 or higher -- by Saturday afternoon.

Sam started the day Thursday with winds of 35 mph and ended the day at 70 mph, signifying a rapid intensification, which occurs when a tropical cyclone strengthens by at least 35 mph in 24 hours.