MIAMI — As Hurricane Dorian plowed toward the Florida coast on Thursday, the predictions became more dire, the preparations more urgent, the disruptions more immediate.

By the time the storm makes landfall on Monday, forecasters warned, it could be an extremely powerful Category 4 hurricane with sustained winds of 130 miles per hour, driving a deadly storm surge and causing catastrophic damage. Exactly where that would happen was still unclear, so Florida’s entire Atlantic coast was on alert Thursday, with residents from Miami to Jacksonville crowding sandbag-filling stations and rushing to grocery stores.

[Here is the latest coverage on Hurricane Dorian as it batters the Bahamas.]

“It looks like Thanksgiving,” said Elizabeth Eradiri, who works at a Publix supermarket in Fort Pierce. “It didn’t look like this yesterday. They’re buying everything you can think of — but mostly water.”

If the forecast holds, Dorian would be the first hurricane of Category 4 or higher to make landfall on Florida’s east coast since 1992, when Andrew, a Category 5 storm, ripped through the Miami area. But with Dorian spinning and gathering energy about 300 miles northwest of Puerto Rico on Thursday evening, its likely route toward the Bahamas and then the United States mainland remained maddeningly difficult to pin down with any precision.