Hurricane Dorian is on track to strengthen to a powerful Category 4 hurricane with possible life-threatening storm surge and dangerous winds as it slams into Florida’s east coast at the end of Labor Day weekend, forecasters said Thursday.

“Strengthening is forecast during the next few days, and Dorian is expected to become a major hurricane on Friday,” the National Hurricane Center said Thursday. Landfall on Monday is possible anywhere between the Florida Keys and southern Georgia, forecasters said.

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Florida Gov. Ron DeSantis declared a state of emergency for 26 counties in Dorian’s possible path and said he spoke with President Donald Trump on Wednesday evening about storm preparations.

“Every Florida resident should have seven days of supplies, including food, water and medicine, and should have a plan in case of disaster,” DeSantis said in a statement.

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Dorian left the Caribbean relatively unscathed as it pushed past Puerto Rico and the U.S. and British Virgin Islands on Wednesday.

At 11 a.m. Thursday, Dorian was about 370 miles east of the southeastern Bahamas and heading northwest at 13 mph. With winds up to 85 mph, Dorian was a Category 1 hurricane but forecast to reach 130-mph wind as it approaches Florida on Monday.

Threats of storm surge, powerful winds and heavy rains all loomed for Florida and the Bahamas, though the hurricane’s exact path as it nears the U.S. remains uncertain.

Ken Graham, director of the National Hurricane Center, said Thursday that the storm will be slow moving as it approaches land, meaning it can dump more rains and bring more winds across Florida. He said tropical-storm force winds are set to arrive Sunday, so preparations to board windows and stock up on supplies need to be done through Saturday.

Parts of the southeastern U.S. could be drenched in 4 to 8 inches of rainfall, with isolated patches up to a foot.

Models of the storm’s possible track after landfall vary widely, ranging from a turn up the east coast or the Florida peninsula to a track reaching west into the Gulf, says Ryan Truchelut, WeatherTiger chief meteorologist.

In a tweet Thursday morning, Trump described Puerto Rico as “in great shape” after the storm’s fury largely avoided the island. However, he warned Floridians to prepare.

“Florida get ready! Storm is building and will be BIG!” he tweeted.

Officials in Puerto Rico and the Virgin Islands breathed a sigh of relief as they assessed minimal impacts from Dorian.

“We’re happy because there are no damages to report,” said William Solís, the mayor of Culebra, a small Puerto Rican island. One community lost power, he said.

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Island-wide blackouts affected St. Thomas and St. John in the U.S. Virgin Islands, and St. Croix had scattered outages, government spokesman Richard Motta said.

“We are grateful that it wasn’t a stronger storm,” Motta said. Trees and only one electric pole were downed. 

Similarly, the British Virgin Islands saw no major damage, Gov. Augustus Jaspert said.

Meanwhile, far off the mid-Atlantic coast, Post-Tropical Cyclone Erin continued to move northeast, and hit parts of Canada as a weaker tropical storm Friday, forecasters said.

Contributing: Jeff Burlew, Tallahassee Democrat; The Associated Press. Follow USA TODAY’s Ryan Miller on Twitter: @RyanW_Miller