First Identified South Atlantic Cyclone

Reference

• http://www.sbmet.org.br/publicacoes/informativo/2005_07/index.html
• http://www.ncdc.noaa.gov/oa/climate/research/2004/hurricanes04.html#pre

Discussion

This was the first recorded hurricane in the South Atlantic basin since geostationary satellite records began in 1966. This storm came ashore along the coast of Brazil at Santa Catarina on March 28th with sustained winds of 65-70 kts (75-80 mph) and gusts of 85 kts (95 mph). At least 3 people died and 38 were reported injured as a result of the storm. Hurricanes typically do not form south of the equator in the Atlantic due to higher windspeeds aloft, generally preventing the storms from gaining height and therefore strength. Researchers at the National Hurricane Center (US) concluded:

1. The evolution of Cyclone Catarina strongly resembled that of a subtropical-origin North Atlantic hurricane.
2. The conventional satellite-based tools used to estimate the intensity of tropical cyclones agreed that Catarina was of hurricane strength.
3. Microwave-based satellite intensity estimates agreed with the conventional estimates.
4. AMSU microwave data clearly showed the presence of a warm core, particularly near the top of the eye.
5. Sea surface temperatures during the evolution were 23°-24°C, with Catarina moving over 25°C water just before landfall. These temperatures have been observed for the formation of some North Atlantic tropical cyclones and were just below the ‘normal’ 26°C ‘threshold’ for tropical cyclone development. so fundamentally, (f) All available data suggest that Catarina was a hurricane, the first known hurricane of record in the South Atlantic Ocean.

Detailed information regarding this hurricane is available from the the Sixth International Workshop on Tropical Cyclones available at (please note that this is a 3.5 Meg file): http://severe.worldweather.org/iwtc/document/Topic_2a_Pedro_Silva_Dias.pdf