Spiral Storm Swirls Toward Southern Brazil, but Scientists Disagree on Whether It's a Hurricane

AP ^ | Mar. 27, 2004

[nuconvert]

Spiral Storm Swirls Toward Southern Brazil, but Scientists Disagree on Whether It's a Hurricane

Mar 27, 2004

By Bernd Radowitz/ Associated Press Writer/

RIO DE JANEIRO, Brazil (AP) - A large storm spiraled toward the southern Brazil on Saturday as a debate raged between Brazilian and U.S. meteorologists over whether it was a hurricane. The U.S. National Hurricane Center in Florida estimated the storm was a full-fledged, Category I hurricane with winds of between 75 and 80 mph, making it the first hurricane ever spotted in the South Atlantic. AccuWeather, Inc., a private forecasting company, said it also considered the storm a hurricane.

Brazilian scientists disagreed, saying the storm had top winds of 50 to 56 mph, far below the 75 mph threshold of a hurricane. The state of Santa Catarina put its civil defense on alert Saturday night, warning of high waves.

The U.S. forecasters said the worst part of the storm would hit Brazil early Sunday somewhere between the cities of Florianopolis and Porto Allegre, a span of about 130 miles. The Brazilians said the storm could peter out before then.

"Winds and rains will not be significant, so we don't need to alarm the population," said meteorologist Dr. Gustavo Escobar of the Brazilian Center for Weather Prediction and Climatic Studies.

U.S. scientists said they were baffled by the Brazilian position.

"We think the Brazilians are, quite frankly, out to lunch on this one," said Michael Sager, an AccuWeather meteorologist. "I think they're trying to play it down and not cause a panic. I don't know what they're doing, but they're obviously wrong."

All sides said they were basing their estimates on satellite data, since the United States has no hurricane hunter airplanes in the area and Brazil doesn't own any.

Satellite images showed a spiral-shaped mass of clouds with an open area in the center. Escobar called it an "extra-tropical cyclone."

Sager said the storm had a clear, well-defined eye and that it had lasted for more than 36 hours. Storms that are not hurricane-strength sometimes form strong eyes, but not for that long, he said.

Kelen Andrade, another meteorologist with the Brazilian center, said the storm was swirling only in a clockwise motion and was not showing motion in the opposite direction at higher altitudes, another mark of a hurricane. Sager disagreed.

"If you know what you're looking at, you can see that counterrotating quite readily," he said.

He predicted the storm would make landfall at hurricane strength just before dawn near the town of Torres.

Earlier Saturday, the outer edges of the storm brushed the coast of Brazil's southern Santa Catarina state with winds estimated at about 25-30 mph and moderate rains, Escobar said. The area is about 430 miles south of Rio de Janeiro.

Winds in nearby Florianopolis, a city of 700,000, were only about 12 mph, rainfall was mild, and no damage was reported, said meteorologist Kelen Andrade.

Jack Beven, a hurricane specialist at the National Hurricane Center in Miami, said the eye of the storm was near 29 degrees south latitude and 48 degrees west longitude by Saturday evening. That would place it about 50 miles east of the city of Laguna.

"To us, it has all the satellite appearance and intensity of a hurricane," Beven said. "I don't know what data (the Brazilians) are looking at. They may have data services locally that don't go out on the national data service."

He said no agency is sending out regular hurricane advisories on the storm.

"Down there, this is such a rare and unique event. The whole situation is strange," Beven said. "We're trying to help out, but because of the uniqueness of this event, it may be out of their expertise to some degree."

[nuconvert]

"We think the Brazilians are, quite frankly, out to lunch on this one,"

LoL

[Kirkwood]

Brazilians are a bit like the French. They would rather be wrong and suffer the consequences than to be right if it means agreeing with Americans. But they are still much more likable than the French, IMO.

[Viking2002]

Brazillian meteorologists are either burying their heads in the sand, or they don't know a hurricane from a hole in the ground. Either way, the lot of them should be fired after it makes landfall.

[Crazieman]

Water Vapor Imagery, I point clearly defined outflow bands from the slight high pressure center that sits over a hurricane causing the counterrotation effect. This basically keeps the hurricane well ventilated.
Note the clearly defined eye and how it persists in the images. You'll also notice more outflow on the south side as the counterrotation remaines persistant.

Visable satellite photo


No, I'm not a meteorologist by trade, but I've studied it almost as long as I could lift a book and read it. Two subjects that have kept my fascination are meteorology and astronomy.

[blam]

[nuconvert]

Very nice.
Thank you.

[Bob]

Am I missing something here? I would have expected that the rotation would be counter-clockwise since it's south of the Equator.

[Crazieman]

The outflow rotation is counter-clockwise because it is a slight high pressure center above the hurricane. The main system rotates clockwise.

The reverse is true for the northern hemisphere.

The high cirrus I point out are the outflow bands.

[Bob]

It must be a while since I've seen images of a hurricane in the northern hemisphere. I'll do a search to refresh my memory on what they look like.

[Bob]

I had forgotten just what a northern hemisphere hurricane looked like. Thanks for your clarification.

[sonofatpatcher2]

Why are hurricanes so rare in the South Atlantic?

[Fiddlstix]

Just wait till it makes landfall. Then see what tune they'll sing.

[sonofatpatcher2]

Re: Why are hurricanes so rare in the South Atlantic?

From: http://ww2010.atmos.uiuc.edu/(Gh)/guides/mtr/hurr/glob.rxml

The Southern Hemisphere also experiences tropical cyclones. However, they are confined to the Western Pacific and Indian Oceans. Even though ocean temperatures are warm enough, a small region without tropical cyclones exists near the equator. This is because for all the thunderstorm activity that may exist, the coriolis force here is not sufficiently large enough.

and from: http://ww2010.atmos.uiuc.edu/(Gh)/wwhlpr/coriolis.rxml?hret=/guides/mtr/hurr/glob.rxml

Coriolis Force is an artifact of the earth's rotation- Once air has been set in motion by the pressure gradient force, it undergoes an apparent deflection from its path, as seen by an observer on the earth. This apparent deflection is called the "Coriolis force" and is a result of the earth's rotation.