"There's problems that happen when hurricanes occur in areas that we've never seen before," said hurricane center meteorologist Eric Blake last week.

The storm was a Category 1 hurricane - the least powerful on forecasters' five-level scale - with winds somewhere between 74 and 95 miles per hour.

"It's about 225 miles east-southeast of the Brazilian coast and it's moving westward at about 7 miles per hour ," he said.

Blake said some of the forecasting computer models showed the storm turning away from the coast before making landfall, but he said it was too soon to say if that would happen.

"It has an eye and thunderstorms around the center, and we're looking at the possibility of (landfall in) southeast Brazil sometime tomorrow or the next day," he said.

The storm has not been given a name because it has formed in an area where meteorologists have made no provision for doing so. In parts of the world where storms usually form, forecasters assign men's and women's names in alphabetical order to help keep track of them.

It was too soon to say if the hurricane would break up before it made landfall.

"Right now it's too early to tell. There's nothing obvious to say this storm is going to weaken," Blake said. He noted that it is autumn in Brazil, an active time of year in regions that normally have hurricanes, such as the Atlantic Ocean off the U.S. east coast.

Ship captains have reported hurricanes for centuries and, since the 1960s, weather forecasters have used satellites to track storm activity around the globe.

But a hurricane has never previously been reported in the south Atlantic. Blake said there have been "questionable" tropical weather systems tracked in the area before, but none had developed into a hurricane.