FORT LAUDERDALE, Fla. – It must be August, because South Florida is in the cone of uncertainty. Bulking up quickly, Tropical Storm Chris emerged in the western Atlantic on Tuesday, threatened to intensify into a minimal hurricane and take aim for the Florida Straits by Sunday.

For now, Cuba and the Florida Keys appear most under the gun, as the forecast track takes the system just north of Havana. Several models point the storm across Cuba or south of it.

However, even on its projected path, it could graze South Florida and bring stormy conditions. Because long-range forecasts can hold large errors, there also is the possibility it could veer in the direction of South Florida. If so, the region could start feeling it on Saturday, forecasters said.

“We have shifted the track farther to the south, but we can’t rule out South Florida this early in the game,” said meteorologist Jennifer Pralgo, of the National Hurricane Center. “So people really need to monitor this thing.”

Late on Tuesday, Chris, the third named storm of the 2006 season, was about 300 miles southeast of San Juan, Puerto Rico, moving northwest at 10 mph with sustained winds of 60 mph. It was about 1,300 miles southeast of Miami. The storm was expected to douse the northern Leeward Islands and Puerto Rico with up to 8 inches of rain by Wednesday morning. Tropical storm warnings were posted for those islands, as well as the U.S. and British Virgin Islands.

Although in existence for only a day, Chris already has been unpredictable.

When it intensified into a depression east of the Lesser Antilles at 11 p.m. on Monday, forecasters initially predicted it wouldn’t reach tropical storm strength. It became a tropical storm six hours later.

On Tuesday, forecasters thought it wouldn’t be able to reach hurricane status because of wind shear over it and dry air ahead of it. But a hurricane hunter aircraft discovered it had much stronger winds and much lower pressure than expected.

Now it is forecast to build to a 75 mph hurricane, possibly stronger.

“We were kind of surprised that it had that much wind,” Pralgo said. “It’s in a neutral environment. There’s not that much shear, really.”

The projected path takes the storm north of Hispaniola on Thursday, into the southern Bahamas on Friday and near the north central Cuban coast on Saturday. From there, it was predicted to move into the Florida Straits south of the Keys on Sunday.

If it holds to that track, it’s too early to predict how much rain and wind the system might bring to South Florida, if any, said meteorologist Roberto Garcia of the National Weather Service in Miami.

“It has so much uncertainty,” he said.