NASA's attention has recently been drawn to an unusual event unfolding off the coast of Brazil—a rare tropical storm swirling in the South Atlantic Ocean, a region where such phenomena are infrequent.
The origin of this disturbance traces back to February 15, when a stationary low-pressure front began to take shape. Subsequently bolstered by a surge of tropical moisture, the front evolved into a subtropical depression by February 16, marking the onset of its transformation.
Tropical Storm Akará
Continuing its intensification and southward trajectory, the depression was officially upgraded to Tropical Storm Akará by the Brazilian Navy Hydrographic Center on February 18, registering sustained winds of up to 64 kilometers (40 miles) per hour, according to NASA.
The image of Akará was captured by NASA's Aqua satellite's MODIS (Moderate Resolution Imaging Spectroradiometer) instrument at approximately 2:20 p.m. local time (17:20 Universal Time) on February 19. At that moment, Akará was situated approximately 900 kilometers (560 miles) southeast of São Paulo.
Prior to the 21st century, tropical cyclones in the South Atlantic were not documented. According to meteorologists at Yale Climate Connections, this was mainly due to high wind shear, which inhibited storm formation, and the infrequent occurrence of easterly waves from northern Africa, which are essential for seeding cyclones and hurricanes in the Atlantic, south of the equator.
However, the landscape shifted notably in 2004 when Tropical Cyclone Catarina, a rare phenomenon, materialized and eventually made landfall in Brazil's Santa Catarina state.
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First Hurricane in Satellite Record
The National Hurricane Center in Miami classified the storm as a category I hurricane (named Catarina), marking it as the initial hurricane documented in the South Atlantic within the satellite record, according to NASA.
During that period, the Brazilian Center for Weather Prediction lacked operational anemometers (devices for measuring wind) in the region and did not possess any hurricane hunter aircraft for traversing the storm.
After Catarina, meteorologists intensified their monitoring of storm development in the South Atlantic. Since 2015, three additional tropical storms have been noted in the area, namely Tropical Storm Iba in 2019, Tropical Storm 01Q in 2021, and presently, Akará in 2024.
The warm sea surface temperatures prevalent in the vicinity likely played a pivotal role in Akará's genesis, with temperatures hovering approximately 0.5 degrees Celsius above average, a factor conducive to tropical cyclone development.
Yale Climate Connections observed that this abnormally warm water aligns more with temperatures usually seen in early summer, signifying an ongoing pattern of warm sea surface temperatures lasting for months.
NASA notes that Akará will stay largely offshore, with minimal impacts on land, except for high surf along the coast south of Rio de Janeiro. Predictions indicate that the storm will lose strength as it moves southward into cooler waters.
