TALLAHASSEE, Fla. — Tropical Storm Isaac, expected to become a hurricane shortly, could bring high winds and heavy rain to the Valdosta area in the next three to four days, according to the National Weather Service.

Isaac pushed into Cuba Saturday after sweeping across Haiti’s southern peninsula, where it caused flooding and at least four deaths, adding to the misery of a poor nation still trying to recover from the terrible 2010 earthquake.

Forecasters said Isaac poses a threat to Florida Monday and Tuesday, just as the Republican Party gathers for its national convention in Tampa, which scrapped its first day of activities as a precaution.

It could eventually hit the Florida Panhandle as a Category 2 hurricane with winds of nearly 100 mph.

The “cone,” or possible path of the storm, stretches from Mississippi to Lake City, Fla., said Kelly Godsey, meteorologist with the National Weather Service’s Tallahassee, Fla., office.

“It’s too early to say where it will make landfall,” he said. “There’s a lot of uncertainty.”

Godsey said there’s a 40 percent chance Isaac could bring tropical force winds to Valdosta in the next three to four days, depending on where the storm comes ashore.

“Rain could be locally heavy,” he said, putting the possible rainfall in Valdosta between 10 and 15 inches.

The latest forecasts put the greatest threat of landfall between Mobile, Ala., and Apalachicola, Fla., Godsey said. “But a lot could change in three to four days,” he said.

Isaac’s center made landfall just before midday near the far-eastern tip of Cuba, downing trees and power lines. In the picturesque city of Baracoa, the storm surge flooded the seaside Malecon and a block inland, destroying two homes.

Florida Gov. Rick Scott declared a state of emergency, officials urged vacationers to leave the Florida Keys and the U.S. National Hurricane Center said a

hurricane warning was in effect there, as well as for

the west coast of Florida from Bonita Beach south to Ocean Reef and for Florida Bay.

At least four people were reported dead in Haiti including a 10-year-old girl who had a wall fall on her, according to the country’s Civil Protection Office. There were no immediate details on how the others died.

The government also reported two injuries; “considerable damage” to agriculture and homes; nearly 8,000 people who were evacuated from their houses or quake shelters; and more than 4,000 who were taken to temporary shelters.

Forecasters predicted the storm would likely march up through the Gulf of Mexico and approach the Florida Keys on Sunday, then continue north off the state’s west coast as a hurricane on Monday.

Tampa is within the tropical storm watch zone, meaning forecasters believe tropical storm conditions are possible there within the next 48 hours.

Republican officials abruptly announced plans Saturday evening to scrap the first day of their national convention, which was scheduled to begin Monday in Tampa.

“Our first priority is ensuring the safety of delegates, alternates, guests, members of the media attending the Republican National Convention, and citizens of the Tampa Bay area,” party chairman Reince Priebus said in an emailed announcement that followed private conversations involving presidential candidate Mitt Romney’s campaign, security officials and others.

Priebus added that forecasters have predicted that convention-goers “may encounter severe transportation difficulties due to sustained wind and rain” on Monday, the day the convention had been scheduled to open.

The announcement said that while the convention would officially be gaveled into session on Monday as scheduled, the day’s events would be cancelled until Tuesday.

Gov. Scott said during a media briefing that delegates were being told how to stay safe during a storm, and officials were ready for storm surge, bridge closures and other problems that could arise during the convention.

After hitting land near the easternmost tip of Cuba on Saturday, Isaac’s center spent just a few hours over the island before reemerging into the water, where it was expected to pick up strength.

On Saturday afternoon, the storm was centered about 120 miles east of Camaguey, Cuba, with maximum sustained winds of 60 mph, the Hurricane Center reported. It was moving northwest along the Cuban coastline at 21 mph.

Tropical storm-force winds extended nearly 205 miles from the center, giving Isaac a broad sweep as it passed.

In Baracoa, authorities cut off electricity as a preventive measure. Civil defense officials patrolled the streets and told onlookers to be careful as they gawked at the powerful surf kicked up by the storm. Waves crashing against the seawall sent spray high into the air and deposited rocks and other debris on land.

Dariel Villares and a cousin who lives next door lost their seaside homes.

“A high wave came and knocked down both walls: mine and my cousin’s,” Villares said. “Now we’re removing everything of value.”

There were no reports of fatalities, Red Cross worker Javier de la Cruz said.

Flooding was reported in low-lying coastal areas and 230 people were in emergency shelters, according to state TV.

In central Cuba, far to the west of Baracoa, the Sol Cayo Coco beach resort moved guests out of ground floor rooms. Intermittent rains and gusty winds buffeted Havana, 560 miles (900 kilometers) away.

Cuba has a highly organized civil defense system that goes door-to-door to enforce evacuations of at-risk areas, largely averting casualties from storms even when they cause major flooding and significant damage to crops.

Near the island’s southeastern tip, the U.S. military suspended ferry service at the Guantanamo Bay naval base and bunked guards inside prison facilities, but operations were returning to normal by late afternoon.

“The bad weather did not materialize here as tropical storm Isaac turned away,” Navy Capt. Robert Durand said.

Authorities in the Dominican Republic evacuated nearly 7,800 people from low-lying areas, and at least 10 rural settlements were cut off by flooding, according to Juan Manuel Mendez, director of rescue teams. Power was knocked out in parts of the capital, Santo Domingo.

There were no reports of injuries, but 49 homes across the country were destroyed.

Authorities discontinued a tropical storm warning, but rainfall was expected to reach up to 12 inches (300 millimeters) over the weekend.

“We still have a big cloudy area over the island that will produce lots of rain” until Sunday afternoon, said Francisco Holguin of the local meteorological agency.