Forecasters tracking first-ever South Atlantic hurricane

By Jack Williams, USATODAY.com

The first hurricane ever known to have formed over the South Atlantic Ocean could threaten the coast of Brazil by early next week.

First South Atlantic hurricane ever known is at the lower right.

NOAA GOES satellite

Satellite images "give all the appearance of a hurricane" with sustained winds faster than 75 mph, says Jack Beven of the U.S. National Hurricane Center in Miami. But no ships have reported wind speeds from anywhere near the storm.

He and other hurricane specialists at the Center are helping Brazil's civilian and military forecasters track and predict the storm, something Brazilian meteorologists have never had to do.

Friday afternoon the storm was centered about 260 miles east of Florianopolis, Brazil, and is likely to continue moving slowly to the west and maybe turn to the south to miss Brazil completely. (Related: Forecasts for Florianopolis, Brazil)

While the National Hurricane Center is working with Brazilian meteorologists, Brazil would issue any needed storm advisories.

"We are trying to run our hurricane forecast models, but they are structured for the North Atlantic," Beven says. "Some just flat out refused to run."

Computer models that are working disagree with one saying the storm could hit Brazil, and the other two saying it should turn to the south, but with the two disagreeing on how close to land it will be when it turns.

The storm has no name since unlike in the parts of the world where hurricanes and similar storms are common, forecasters have never made a list of South Atlantic names.

Beven says meteorologists can't be sure that a hurricane never formed in the South Atlantic before satellites begin keeping an eye on all of the world's oceans in 1960. In fact, Bevin said, if a hurricane had formed before 1960 where the new one is now located, no one would have known about it.

Meteorologists, know of two South Atlantic storms that probably reached 39 mph tropical storm strength.

The latest formed Jan. 19 of this year east of Salvador, Brazil, but weakened before "drifting" ashore, Beven says.

A storm that formed off the coast of Africa in April 1991 is also believed to have reached tropical storm strength, but like the January storm, did not come close to growing into a 75 mph hurricane.

While the tropical part of the South Atlantic Ocean has large areas with the 80-degree or warmer ocean temperatures needed to sustain hurricanes, upper atmosphere winds are usually blowing much faster than winds near the surface or in the opposite direction. Such "wind shear" can rip apart storms before they grow into hurricanes.