(CNN) -- Ernesto became the first hurricane of the 2006 season on Sunday and is forecast to hit central or northern Florida by Thursday morning.
Hurricane Ernesto had top winds of 75 mph at 8 a.m. ET, with higher gusts, according to the National Hurricane Center.
An advisory from the hurricane center said conditions in the Gulf were "highly conducive" for the "rapid intensification in the near term and for the potential development of a major hurricane in the longer term." (Watch where Ernesto is likely to hit -- 1:03)
Earlier fears that Ernesto might barrel toward New Orleans, near the anniversary of Katrina's landfall, were eased with the latest advisory, but it was bad news for residents of central and northern Florida.
Ernesto is now forecast to make landfall as a major category 3 storm on the coast of Florida, move northeastward and still be a category 1 storm well inland.
A tropical storm watch may be issued for the western portion of the Florida Keys sometime Sunday, according to the discussion notes issued by the hurricane center.
Just how powerful the hurricane becomes will be "highly dependent on the exact track that Ernesto takes due to land interaction with Haiti and Cuba," the center said.
"If Ernesto doesn't linger over Cuba for more than 24 hours, then major hurricane strength seems likely" by Thursday or Friday, the hurricane center said.
As of 8 a.m. ET Sunday, the storm was centered about 115 miles south-southwest of Port au Prince, Haiti, and it was moving at 9 mph toward the northwest, the center said.
Hurricane Ernesto's center should "pass very near" the southwestern tip of Haiti Sunday afternoon or early evening and be near Cuba's southeastern coast Monday morning, the hurricane center said.