First Comes Bonnie ...

Florida braced for a potential double dose of hurricanes Thursday, ordering Florida Keys visitors to get out of Hurricane Charley's path and preparing for possible flooding as Tropical Storm Bonnie approached the already soaked Panhandle.

Bonnie, which is approaching hurricane strength, is expected to hit the state early Thursday, at least 12 hours earlier than Charley. The prospect of back-to-back hurricanes prompted Gov. Jeb Bush to declare a state of emergency for all of Florida as schools and government offices announced closures and forecasters warned residents to prepare for the worst.

CBS News Meteorologist George Cullen says a back-to-back hit of this type hasn't happened in Florida since Oct. 17, 1906, when two tropical storms hit the state.

"It's never happened in our lifetime," says Cullen of the prospect that the two storms could come ashore on the same day in the Sunshine State.

The National Hurricane Center issued a hurricane watch or warning for most of northwest Florida, from the Alabama border to the Suwannee River, because of Bonnie. The warning means hurricane conditions are possible within a day, while the watch means within 36 hours.

CBS News Correspondent Aleen Sirgany reports in the Florida panhandle, officials are more worried about the water than they are about the wind. The risk of flooding is high, with a possible four foot storm surge rolling into an area that has already been drenched with seven inches of rain.

Charley grew to hurricane strength around midday Wednesday before spinning by Jamaica. A few rooftops were reported damaged in the capital of Kingston, where residents rushed to supermarkets to buy bottled water, flashlights and other emergency items before the storm hit. The country's main airports were shut down and cruise lines were diverted.

Charley prompted a hurricane watch for the Florida Keys and Florida Bay, at the state's southern tip, north to Anna Maria Island, on the southern edge of Tampa Bay. Watches also were issued for the southwestern Florida mainland from Flamingo to just north of Naples, and western Cuba. A hurricane warning was issued for the Cayman Islands.

Charley is forecast to hit or pass close to the lower Keys late Thursday, then hit the southwestern Florida mainland early Friday with winds of 85-105 mph.

Monroe County emergency officials told visitors to evacuate the entire 100-mile-long island chain. The trip can take several hours because there's only one road, the Overseas Highway, from Key West to Key Largo and only two linking Key Largo to the mainland. Residents were not being told to leave.

Key West Mayor Jimmy Weekley asked bars, shops and restaurants to shut down at 10 p.m. Thursday, saying the city would offer new guidance after the storm blew by.

Lisa Kaminski, a manager at a Days Inn in Key West, told the hotel's approximately 200 guests they had to leave, as well as warning those with reservations.

"We're telling people that the hurricane will probably be here Friday and it's in their best interest not to come," she said.

The Key West native said she and her employees weren't too worried about Charley, though: "We're staying. This isn't a big one."

Plenty of tourists did what they were told Wednesday and cleared out, slow and steady on the single road that runs through the Florida Keys.

"It's gonna cut off a few days of our vacation - we've had this planned since February, so it's kind of disappointing," said Pam Nickel, one of many reluctantly cutting short her vacation.

Officials in Collier County, which contains Naples, were requesting the voluntary evacuation of residents and tourists in coastal areas, emergency services spokesman John Torre said. Neighboring Lee County, which contains Fort Myers, also was warning people to consider leaving.

Gov. Bush activated the Florida National Guard to prepare to respond to any damage and said more evacuations may be needed. Public schools were scheduled to be closed Thursday and Friday in the Keys, while schools and government offices were to be closed Thursday in parts of the Panhandle.

At 11 p.m. EDT Wednesday, Charley had top sustained winds of about 75 mph and is expected to strengthen. It was centered about 195 miles east-southeast of Grand Cayman, moving west-northwest at 17 mph.

In the Caymans, the storm's center is forecast to pass between Grand Cayman and two smaller sister islands on Thursday; government offices were closed and beach bars put up sandbags.

Charley is expected to remain at hurricane force when it passes over central Florida, but the storm could go anywhere from Miami to the Panhandle. Three to six inches of rain is expected, with locally higher amounts possible, according to hurricane center forecaster Daniel Brown.

Bonnie, at 11 p.m. Wednesday, was centered about 260 miles south of Apalachicola, moving northeast at around 12 mph, with tropical storm force winds extending 70 miles from the center. Bonnie was expected to make landfall along the central Panhandle Thursday morning, when isolated tornadoes were also possible, forecasters said.

Bonnie could dump 4 to 6 inches of rain, leading to coastal storm surges 2 to 4 feet above normal.

Because the Panhandle is already soaked from days of rain from a different system, some low-lying areas may have to be evacuated if there's flooding, said Craig Fugate, the state's emergency management director.

The storms have forced ships to change their routes in Florida, which has the busiest ports in the world for cruise ship traffic. Carnival Cruise Lines is reshuffling the ports of call for several ships to avoid the storms, and Royal Caribbean Cruises Ltd. is doing the same.

According to Hurricane Center projections, after Florida, both storms could spread rain along the East Coast. Heavy rain from the storms was forecast for North Carolina, just a week after Hurricane Alex damaged parts of that state's Outer Banks.

Bonnie and Charley are the second and third named storms of the Atlantic hurricane season, which runs from June 1 to Nov. 30.