Dorian strengthens to hurricane as it slams Caribbean, may hit Florida as Category 3 Dorian is forecast to steer toward Florida over the Labor Day weekend.

Dorian strengthened to a Category 1 hurricane Wednesday, lashing the U.S. and British Virgin Islands with heavy rain.

The entire British Virgin Islands lost power at the height of the storm, according to the British Islands Department of Disaster Management. Partial power was restored to one-third of the island by 9 p.m. Almost 40,000 customers were without power on the U.S. Virgin Islands at about 5 p.m. on Wednesday, but that number slowly eased throughout the night.

The storm was initially forecast to hit Puerto Rico, but made a major shift and is now not expected to hit the island directly. It is expected to pass through the east of the island Wednesday evening, bringing 80 mph winds, 10 inches of rain and possibly flash flooding. Tropical storm and hurricane warnings were discontinued late Wednesday.

As it heads north and strengthens, it is forecast to become to a Category 3 hurricane when it reaches Florida over the Labor Day weekend.

Residents in Puerto Rico had been preparing for the worst. Many Puerto Ricans are still reeling from the devastation of 2017's Hurricane Maria, including tens of thousands of residents living under blue tarp roofs.

But Puerto Rico's governor, Wanda Vazquez, said the island was fully prepared for Dorian.

President Donald Trump has approved an emergency declaration, which will provide federal assistance to the island.

"The communication with all [of the president's] aides has been extraordinary," Vazquez said Monday.

A new Federal Emergency Management Agency (FEMA) representative is also on the island assisting in response coordination.

Once Dorian passes through the Caribbean, it's forecast to steer toward Florida over the Labor Day weekend.

Dorian could make landfall on the East Coast of Florida on Monday morning as a Category 3 hurricane with winds up to 115 mph.

The entire east coast of Florida from Miami to Jacksonville is forecast to see impacts.

Florida Gov. Ron DeSantis has declared a state of emergency for counties in Dorian's path.

"It’s important for Floridians on the East Coast to monitor this storm closely," DeSantis said in a statement. "Every Florida resident should have seven days of supplies, including food, water and medicine, and should have a plan in case of disaster."

Jacksonville will activate its emergency operations center full-time as Dorian nears, Mayor Lenny Curry said at a news conference Wednesday.

Curry said it's too early to make any decisions about possible evacuations, but residents should make sure they know their evacuation zone.

The storm is also impacting Labor Day travelers. Some airlines have issued travel waivers, and Royal Caribbean is closing its private island in the Bahamas for a week and altering some of its cruise ship itineraries to avoid Dorian.

As the Atlantic hurricane season nears Sept. 10 -- its peak -- Dorian isn't the only storm on the move. Newly formed Tropical Storm Erin is expected to bring rough surf to the East Coast beaches from the Carolinas to New England this Labor Day weekend.

Otherwise, it is not expected to directly impact the East Coast.