PORT-AU-PRINCE, Haiti >> Tropical Storm Isaac strengthened slightly as it spun toward the Dominican Republic and vulnerable Haiti today, threatening to bring punishing rains but unlikely to gain enough steam to strike as a hurricane.

Forecasters now expect the storm to stay below hurricane force until it’s in the Gulf of Mexico, staying to the west of Tampa, Florida, where the Republican National Convention starts on Monday, though there is still an outside chance it could hit there.

Forecaster Eric Blake of the U.S. National Hurricane Center said it is “too early to know” the storm’s exact course, though projections indicated the storm could make U.S. landfall near the Alabama-Mississippi border.

In Haiti, the government and international aid groups announced plans to evacuate several thousand people from one of the settlement camps that sprang up in the aftermath of the 2010 earthquake.

Isaac was expected to dump eight to 12 inches  of rain on the island of Hispaniola that is shared by Haiti and the Dominican Republic.

“That kind of rain is going to cause some life-threatening flash floods and mudslides,” said Dennis Feltgen, a spokesman for the Hurricane Center in Miami.

Isaac was centered about 165 miles south-southwest of Santo Domingo, the Dominican capital, on Friday morning, and its maximum sustained winds had increased to 60 mph. It was moving west at 14 mph, according to the Hurricane Center.

Tropical force winds extend nearly 200 miles beyond the storm’s center.

In flood-prone Haiti, where the storm’s eye is likely to blow ashore late today, Prime Minister Laurent Lamothe urged people to avoid crossing rivers, to tape their windows, and to stay calm, saying “panic creates more problems.”

Lamothe and other Haitian officials said the government had set aside about $50,000 in emergency funds and had buses and 32 boats on standby for evacuations.

But among many Haitians, the notion of disaster preparedness in a country where most people get by on about $2 a day was met with a shrug.

“We don’t have houses that can bear a hurricane,” said Jeanette Lauredan, who lives in a tent camp in the crowded Delmas district of Port-au-Prince.

Organizers of next week’s Republican National Convention in Tampa said they were working closely with state and federal authorities on monitoring storm as they prepared for the arrival of 70,000 delegates, journalists and protesters, and Florida Gov. Rick Scott said there were no plans to cancel the convention.

Out in the eastern Atlantic, another tropical storm, Joyce, was downgraded to a tropical depression late Thursday, and posed no threat to land. The hurricane center in Miami said Joyce had maximum sustained winds of 35 mph and that it was becoming disorganized.