Hurricane Dorian moved past Puerto Rico and the U.S. Virgin Islands on Wednesday, heading northwest into the Atlantic Ocean and threatening to become a "dangerous hurricane."

Florida, beware.

As of 11 p.m. EDT, Dorian was gaining momentum in the Atlantic's warm water, a Category 1 hurricane with sustained winds of 85 mph, but the National Hurricane Center predicted "marked intensification." Dorian will head toward the U.S. coast as a Category 3 hurricane with winds of at least 111 mph, the weather service said.

"All indications are that by this Labor Day weekend, a powerful hurricane will be near or over the Florida peninsula,'' the weather service said.

Florida Gov. Ron DeSantis declared a state of emergency and urged residents to prepare for the storm's arrival.

On Wednesday, Dorian battered the Virgin Islands, parts of Puerto Rico and its island-municipalities of Vieques and Culebra with powerful winds and heavy rainfall, which could lead to life-threatening flash flooding through Thursday morning.

A hurricane warning was in effect for both U.S. and British Virgin Islands, as well as Vieques and Culebra. Puerto Rico was under a hurricane watch, and 100 flights to and from the main airport were canceled, but the U.S. territory was spared a direct hit.

Stay up to date on Dorian day and night:The Evening Briefing newsletter brings the news straight to your inbox

On Thursday, Dorian should be east of the Turks and Caicos and the southeastern Bahamas, likely growing to a Category 2 hurricane by the evening. By Friday or Saturday, forecasters expect it near or to the east of the central and northwestern Bahamas.

The hurricane was about 90 miles north of San Juan, Puerto Rico, as of 11 p.m. Wednesday, moving at 13 mph.

"Heavy rains are expected to occur over portions of the Bahamas, Florida, and elsewhere in the southeastern United States later this week and into early next week,'' the hurricane center said, urging residents in those areas to monitor the storm.

Nuking a hurricane? You can't nuke a hurricane to stop it, as Trump reportedly suggested. Here's why

President Donald Trump has declared an emergency and ordered federal assistance for Puerto Rico the U.S. Virgin Islands.

Trump tweeted Wednesday morning that he was tracking the storm closely, and he also took a shot at Puerto Rican officials.

"FEMA and all others are ready, and will do a great job. When they do, let them know it, and give them a big Thank You - Not like last time. That includes from the incompetent Mayor of San Juan!" he said.

Dorian has already battered Barbados and St. Lucia this week, downing trees and power lines.

In Puerto Rico, the storm's threat sparked fears as the island continues to recover from the devastation of Hurricane Maria, which wiped out power two years ago.

Ruben Rodriguez, a reporter and editor at Puerto Rico’s leading newspaper, El Nuevo Dia, said residents promptly loaded up on supplied to brace for Dorian.

“After Maria, everybody became an expert in hurricane preparation,'' said Rodriguez, who bought extra food and six cases of bottled water. "As soon as word got out that a big storm was coming, people flooded the stores to buy water.’’

'Absolute nightmare':4 former Florida nursing home staffers charged in 12 Hurricane Irma deaths

Rodriguez and Paco Figueroa, a semi-retired accountant who lives in the eastern town of Ceiba, said those who endured the impact of Maria were left with a sort of whiplash when a major weather system approaches.

Figueroa didn't take any chances and drove early Wednesday to his daughter's house in the San Juan metropolitan area, away from the hurricane's path.

“Maria left a deep scar here, and any storm provokes anxiety among people,'' he said. "That’s understandable, because we haven’t totally recovered yet. There are still a lot of people with those blue tarps for roofs.’’

Top officials say they are prepared this time with better equipment, though some concern persists. José Ortiz, executive director of Puerto Rico’s Electric Power Authority, told the Associated Press that the power system still has some weak areas and could "suffer" given the storm's wind speeds. But he said the agency has thousands of lights, poles and transformers.

Cristobal Jimenez, a community activist who lives in the northeastern city of Fajardo, said he went two months without power after Maria and that many in the island are wondering whether the lights will stay on after the grid repairs.

“Dorian will show whether the distribution lines were glued with bubble gum,’’ Jimenez said.

He also noted that Puerto Ricans have a much better idea now of what it takes to prepare for a hurricane, and they’re better supplied with generators, water filters, solar lamps, food and water.

"I went to help out at the church today and you could see the movement on the street didn’t have the same feeling of desperation as before,'' Jimenez said. "There was some anxiety, but it was along the lines of, ‘I need to get bread. I need to get a couple other small things.’ But it wasn’t the kind of chaos that’s often present.''

Elsewhere in the Atlantic, Tropical Depression Erin is forecast to move northeast, away from the U.S. East Coast. A weakened version of the storm could affect the Canadian Maritimes later in the week, the hurricane center said.

Contributing: The Associated Press. Follow USA TODAY's Ryan Miller on Twitter @RyanW_Miller