(CNN)Once Hurricane Dorian is done thrashing Puerto Rico and the Virgin Islands, southeastern US states could get walloped on Labor Day weekend.
The powerful storm -- which keeps getting stronger -- could strike Florida or Georgia as a Category 3 hurricane by Monday, forecasters said.
"Even up into the Carolinas is not out of the question," CNN meteorologist Chad Myers said Wednesday.
With most of the state's east coast a possible target for Dorian, Florida Gov. Ron DeSantis on Wednesday declared a state of emergency and urged all residents on the coast to get ready for the storm.
But there's a big caveat: It's too early to tell exactly where or when Dorian might strike the US mainland.
Wednesday's projections come five days before Dorian could reach parts of the mainland on Monday.
"The (risk of) error five days out is significant," Myers said. Dorian has already defied projection models as a wild-card storm.
But this much we do know: The cyclone strengthened Wednesday from a tropical storm to a hurricane, whipping 80-mph winds as it pummeled the US Virgin Islands.
"Dorian is forecast to strengthen and become a powerful hurricane during the next few days over the Atlantic waters," the National Hurricane Center said Wednesday afternoon.
Dorian is now a Category 1 hurricane, meaning its maximum sustained winds are between 74 and 95 mph.
It could become a Category 2 hurricane if those winds reach 96 to 110 mph. If Dorian reaches the US mainland as a Category 3 hurricane, it would hurl winds stronger than 111 mph.
Regardless of what you call Dorian, it could deluge parts of the coastal US Southeast with 4 to 8 inches of rain, and up to 10 inches in isolated areas, the National Hurricane Center said.
"This rainfall may cause life-threatening flash floods," the hurricane center said.
The Florida Department of Emergency Management on Wednesday said residents should have seven days of supplies ahead of the storm and provided a supply kit checklist.
"It's important for Floridians on the East Coast to monitor this storm closely," Gov. DeSantis said in declaring the state of emergency. "Every Florida resident should have seven days of supplies, including food, water and medicine, and should have a plan in case of disaster."
One of Dorian's possible targets on the US mainland is Jacksonville, Florida.
Forecast models for Dorian, as of 2 p.m. ET Wednesday.
"We're still a day or two away from making any decisions about any evacuations," Jacksonville Mayor Lenny Curry said Wednesday.
But he urged residents to prepare emergency kits and find their evacuation zones on the Jax Ready app or at JaxReady.com.
The mayor warned that damage from Dorian could come in different forms.
"Will it be the wind? Will it be the flooding? Will it be downed power lines?" Curry said. "The impacts are unpredictable."
In Georgia, Gov. Brian Kemp said he's not yet declaring a state of emergency, but preparations are underway, including for evacuations from Florida into Georgia and away from the Georgia coast.
"The best we can do is prepare for it, protect your belongings, protect your home," Kemp said at a press conference Wednesday. "And make sure that you're ready to move very quickly in the next 24 hours or so."
