In Haiti, meanwhile, the death toll continued to grow and officials were still assessing widespread damage.

The Office of Civil Protection confirmed seven deaths — up from four previously reported. The deaths included a young man killed in a landslide in DonDon, a town in northern Haiti, and a 10-year-old girl who was killed when her home collapsed north of Port-au-Prince.

In the tourist town of Jacmel, in Haiti’s southern peninsula, the damage was pronounced. Houses were still standing but crops, and livelihoods, were washed away.

Isaac’s encounter with Haiti weakened the storm and, tracking near the coast of Cuba for much Sunday, it failed to pull itself into a hurricane before it approached South Florida. Top wind speed in the Keys was a 70 mph gust measured at 2 p.m. at the Smith Shoal Light about 11 miles northwest of Key West. Gusts of 66 mph were recorded at Virginia Key in Miami and 64 mph at Port Everglades in Fort Lauderdale.

But the worst was over pretty early, as Isaac’s track shifted to the west and the storm accelerated. Rather than getting stronger as it moved off Cuba, Isaac weakened a bit as its center skirted just south of Key West after a meandering journey across the Caribbean.

David Zelinsky, a meteorologist at NHC, said the storm hugged Cuba closely enough to disrupt its formation but it will fuel up on the warm Gulf of Mexico and there is nothing in the atmosphere likely to beat it down.

“It may take a little longer to become a hurricane but we’re still forecasting that,” he said.

Zelinsky cautioned Isaac could be stronger than the Category 2 now forecast. Pinpointing intensity is difficult, he said, and the average error two days out is a full category, plus or minus. The worst damage could come via storm surge, which could reach six to 12 feet on the stronger, right side of Isaac.

There also was considerable uncertainty about its path along the Gulf Coast. “Two of our best performing models are at opposite ends of the spectrum,” said Zelinsky. “One turns it farther right toward Florida, the other goes left.”

Either way, both scenarios suggested a nasty couple of days in Tampa, scene of this year’s Republican National Convention — no direct hit but a possible storm surge and certainly rain and tropical force winds.

Florida Gov. Rick Scott canceled a Monday speech at the convention and cleared his calendar to deal with Isaac, wherever it struck.

“We may need to help out other states,’’ he said.

In Homestead, where Isaac’s heaviest rains fell — upwards of four inches — officials appeared to breathe a sigh of relief that Isaac had not caused greater harm, particularly to the city’s significant agricultural industry.

“It looks like we’re dodging a bullet,’’ County Agricultural Manager Charles LaPradd said.

Winter is the busiest season for Homestead’s farmers, but there are still avocados in the groves. Heavy rains can kill avocado trees, and gusty winds can knock the fruit to the ground.

But the storm appeared to cause more damage to small business owners than to farmers.

At about noon, power went out along on Washington Avenue in downtown Homestead, where small shops cater to Mexican, Guatemalan and Central American customers.

About 400 homes and businesses were affected by the outage, among them La Michoacana ice cream shop.

Miguel Chavez, manager of the shop, said he expected losses in the thousands of dollars. The shop has a 10-by-8 foot freezer, as well as display cases filled with ice cream, including flavors not typically found in stores, such as chili pepper.

“Today is a day the hurricane threatens our business,’’ Chavez said after the power outage. “You can’t fight against nature.’’

Miami Herald staff writers Charles Rabin, Carol Rosenberg, Christina Veiga, Kathleen McGrory, Daniel Chang, Carli Teproff and Jacqueline Charles in Haiti contributed to this report.