Tropical Storm Erin is forecast to become a hurricane within the next 24 hours or so as it heads west-northwestward toward the continental U.S.

Hurricane Erin strengthened into a fearsome Category 5 hurricane with sustained winds of 160 mph for much of the day on Aug. 16 as it traveled west just north of the Virgin Islands, according to the National Hurricane Center.

As of Saturday morning, Hurricane Erin had strengthened into a Category 3 storm with maximum sustained winds of up to 120 mph, the National Hurricane Center said.