ORLANDO, Fla. -- The latest projected path for Ernesto shows the storm heading into South Florida as a strong tropical storm and then possibly strengthening into a Category 1 storm over Brevard County, Fla., according to Local 6 News meteorologist Larry Mowry said.

"It may ramp up to a hurricane before it makes landfall in South Florida during Tuesday night into early Wednesday morning," Mowry said.

The track of the storm shifted east again Monday, and the path showed Ernesto passing through Brevard County Wednesday.

"At this point, the storm has the possibility of being over Brevard County as a Category 1 hurricane during the afternoon hours on Wednesday, and then it will lift northward through the overnight hours Wednesday night into Thursday morning," Mowry said.

A state of emergency was in effect for all Florida, because forecasters said Ernesto could potentially threaten a large swath of the state.

Gov. Bush: Don't Underestimate Ernesto

Gov. Jeb Bush warned Floridians to take a potential Category 1 hurricane slamming into the state this week seriously and that the state is preparing for a Category 2 storm during a hurricane briefing Monday.

"Hurricanes are hurricanes," Bush said. "We start thinking, 'Well a Cat. 3 storm -- boy that is bad and I better take this seriously and anything below that, not that important.' That is the wrong attitude. We have been hit by so many hurricanes that I think people start thinking they have the capability of underwriting the risks based on whether the storm is a Category 1, Category 2 or Category 3.

Bush reminded the state that Category 1 Katrina caused problems for the state last year.

"Katrina hit Florida before it hit the Gulf Coast," Bush said. "It was a Category 1 storm -- people died because they were out in the midst of the storm thinking it wasn't a potent storm. It created a lot of hardship for residents of South Florida just as other storms that had been Category 1 had done. We are planning for a Category 2 storm."

Hurricane Watches Issued

Floridians bought gas, water and other supplies and state officials ramped up emergency plans Monday as Tropical Storm Ernesto prompted a hurricane watch for most of the state's densely populated Atlantic coast.

About 400 miles of coast were under the watch from New Smyrna Beach southward on the east coast and from Chokoloskee southward on the west coast, meaning sustained winds of at least 74 mph are possible by late Tuesday night. The Keys were put under a watch on Sunday afternoon because Ernesto could become a hurricane again after it reaches the warm waters north of Cuba, the National Hurricane Center said. Forecasters said there was a 10 percent chance of hurricane-force winds striking South Florida and a 60 percent chance of tropical storm-force winds.

Statewide, about 20 percent of gas stations are now generator-capable, ahead of next year's deadline for most stations to have them, said Jim Smith, president of the Florida Petroleum Marketers & Convenience Store Association.

Officials were developing contingency plans for Florida's Sept. 5 primary election but did not see any immediate cause to delay it, Bush said.

Immediate concern, though, centered on the Keys, where visitors were ordered out and plans were enacted to evacuate special-needs residents to Miami.

In the Keys, three shelters were set to open Monday. All travel trailers and recreational vehicles were ordered out of the Keys, and mobile home residents were also urged to evacuate.

Some residents of the low-lying island chain flocked to grocery stores and home-supply warehouses to stock up on canned goods, bottled water and other storm essentials.

"Key Westers are used to this," said Jim Bernard, assistant manager at a Home Depot in Key West.

Dan Drum, 56, a contractor who has been living in Key West since 1977, was waiting when Home Depot opened early Monday. He said he was going to spend part of the day nailing more roofing screws to a property he owns in Sugarloaf Key.

"I just bought $55 worth of screws. That's all they had," he said.

Miami-Dade County emergency managers were waiting for Ernesto to move closer to decide whether to open shelters or order evacuations, spokeswoman Cynthia Martinez said.

She said officials hoped residents have had hurricane plans since the beginning of the season, but that if not, "now is the time to start making those preparations."

At 11 a.m., the fifth named storm of the hurricane season had top sustained winds of 40 mph, down from 75 mph Sunday. It was centered over Cuba, about 35 miles northwest of Guantanamo and about 485 miles southeast from Key West. It was moving northwest at 10 mph.

Ernesto had been the first hurricane of the season and was 1 mph above the threshold to be a hurricane Sunday, but it weakened as it headed toward Cuba's southeastern corner.

"I don't want anyone to overly focus on the downgrading. ... It has a good chance to regain hurricane status," said Max Mayfield, the hurricane center's director.

The state of emergency directs counties to activate their emergency management offices and activates the National Guard, among other things. Bush canceled several meetings scheduled in New York Monday, and will remain in Tallahassee to monitor storm developments.

A hurricane warning was also issued for Lake Okeechobee in South Central Florida, but Bush said the lake's water level was low, making flooding unlikely.

Ernesto lashed the Dominican Republic and Haiti with heavy rain Sunday, killing one person, and threatened to bring as much as 20 inches of rain to parts of Haiti, prompting fears of mudslides and flooding. The storm was expected to move over Cuba toward Florida, forecasters said.

Watch Local 6 News for more on this story.