A growing Tropical Storm Michelle edged north in the Caribbean Thursday on a slow, uncertain course forecasters warned could threaten Central America, the northwest Caribbean and possibly the United States.

Forecasters also expect Michelle, which already had top sustained winds of near 60 mph, to grow into a hurricane by early Friday. Tropical storms become hurricanes once their top winds reach 74 mph.

"Michelle is in an area where we've seen historically some storms get quite strong because the waters are very warm south of Cuba," said Richard Pasch, a hurricane specialist at the U.S. National Hurricane Center in Miami.

"It looks like it's going to stay in the northwest Caribbean for the next few days. We think it'll move slowly between the north-northwest and the north," he said.

That could take Michelle near the Yucatan Channel separating the Caribbean and the Gulf of Mexico in three days time.

"I don't think that we have any idea where its going because the steering is very weak," Pasch said.

At 4 a.m. EST Thursday, Michelle's was centered at 16.6 degrees north latitude and 83.5 degrees west longitude, or about 235 miles southwest of the Cayman Islands. The storm was moving north at near 5 mph, with a slow north to north-northwestward motion expected during the next 24 hours.

All interests in the northwest Caribbean, throughout much of Central America and parts of the U.S. Gulf Coast should pay close attention to Michelle's development, Pasch said.

"We're not saying there's a direct threat to anybody here in Florida now, but stay tuned," he said.

According to the latest advisory issued by the hurricane center, rains diminished Thursday over Honduras and northeastern Nicaragua.

Before going out to sea Wednesday, Michelle caused significant flooding in Honduras, killing four people and forcing 25,000 residents to evacuate. Nineteen people were missing.

Still, Pasch forecast that the storm might produce flash floods and mud slides over portions of Central America during the next few days. He said heavy local rainfall also was likely over parts of Jamaica and the Cayman Islands.

In southern Florida, water management officials anticipating a possible strike by Michelle on Wednesday announced they were lowering water levels in flood canals on the region's Atlantic and Gulf coasts.