Havana’s Meteorological Institute reported that the storm touched down in Maisi, a municipality east of Guantanamo Saturday afternoon. Radio Baracoa reported that two homes in the island’s easternmost city of 48,000 had collapsed.

But the storm’s drama fizzled at the U.S. Navy base at Guantánamo Bay, Cuba, where the military had scrapped this month’s Sept. 11 terror trial hearings.

“The bad weather did not materialize here,’’ detention center spokesman Robert Durand said.

Forecasters believe the system’s jaunt over Cuba will be brief — and allow the storm more time to strengthen in the warm waters of the Florida Straits. Isaac’s impact depended on how quickly and well the sloppy storm ramped up as it crossed the Florida Straits, with NHC director Knabb saying there was “not a 100 percent guarantee’’ it would reach Category 1 strength by the time it hits the Keys.

But the chances were good it could become the first hurricane to make landfall in South Florida since Category 3 Wilma in 2005. Isaac won’t produce anywhere near the damage, but Miami-Dade and Broward will be on the storm’s “dirty side’’ with the strongest winds. Forecasters predicted the sprawling storm could produce from six to 10 inches of rain and powerful gusts.

In the Keys, which will feel the worst weather, shelters opened, police urged tourists to evacuate and the city’s airport closed.

Frank Gambino, of a Marathon pool service company, is concerned about flooding, especially after 2005 storm flooding reached nine feet.

“I’m making sure I get everything off the floor in case we get some localized flooding,” Gambino said. “We don’t plan on working until Tuesday at least. But it all depends on the severity of the storm.”

Down U.S. 1, Forest Tek Lumber also was busy, but plywood wasn’t flying off the shelves. Most residents in the Keys already have storm shutters or high-impact windows and glass.

Of course, others made the most of the impending storm.

At Key West’s Southernmost Point buoy monument, where television news reporters took turns doing stand-up reports, Chenco Leon took photos of his girlfriend, Jorie Rogers, who was topless save for a Conch Republic flag wrapped around her body.

The two, who moved to the island recently from Indiana, are working on a Key West calendar featuring distinctive pictures of the Island City.

“We prepared. We have canned goods. We took the car to the highest point, over by the cemetery. I’m not too worried. All the locals said it’s a Category 1. Back home we live with tornadoes all the time, so it’s not a big deal here,” Leon said.

Miami Herald staff writers Carli Teproff, Nadege Green, Charles Rabin, Julie K. Brown, Christina Viega, Juan Tamayo, Marc Caputo, Susan Cocking, Carol Rosenberg, David Ovalle and Jacqueline Charles in Haiti contributed to this story.