The Portuguese weather service said that wind gusts of up to 74 mph are possible by the weekend in the Azores, an island chain about 850 miles west of Portugal.
The Category 3 storm will near the coast of the Carolinas Friday.
Florence is joined by Tropical Storm Isaac and Hurricane Helene in this snapshot taken Tuesday some 1 million miles away via NASA's Earth Polychromatic Imaging Camera (EPIC) on the DSCOVR satellite. "This storm is extremely risky". Isaac has maximum sustained winds of 45mph with higher gusts, and officials at Hazard Management Cayman Islands are urging people to keep an eye on the storm's path because it could be heading our way.
This storm is lined up behind Florence in the Atlantic. Tropical Storm Isaac was expected to pass south of Puerto Rico, Hispaniola and Cuba.
The National Hurricane Center downgraded Isaac to a tropical storm overnight but said Tuesday that it could be "at or near hurricane levels" on Thursday, when it approaches the Lesser Antilles Islands. Forecasters also were tracking two other disturbances.
She said: "Helene is moving up from the Atlantic towards us".
Tornadoes: Tornadoes will be possible along and to the right of the track of Florence, including the Midlands, Pee Dee and Catawba Regions, this is especially in SC. Some flooding was forecast early in the day for parts of North Florida, but those forecasts were adjusted later to include high swells and minor coastal flooding at high tide.
Tropical storm warnings have been issued for Martinique, Dominica, and Guadeloupe.
Around six o'clock this morning, the center of Isaac passed 150 miles to the north of Barbados. Regardless of whether a system forms, they say heavy rain and gusty winds are likely along the Texas and Louisiana coast later this week.