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Bomb cyclone threatens southern Brazil

As a low-pressure system moves over northern Argentina and Paraguay beginning this Thursday (Aug. 6), it may develop into an extratropical cyclone with explosive intensification, known as a bomb cyclone. This is also expected to occur as the system moves through the region between Uruguay and the coast of Rio Grande do Sul, Brazil. Notícias relacionadas:Brazil to see up to 127 days of extreme heat per year by 2075.Storms following cyclone still threaten three Brazilian states.According to Micael Cecchini, an astronomer at the Institute of Astronomy, Geophysics, and Atmospheric Sciences at the University of São Paulo (USP), a low-pressure system forms when a mass of very cold air approaches a mass of warm air, and the temperature difference causes a rapid drop in atmospheric pressure between them. In practice, this causes a cyclone. To be classified as a bomb cyclone, or explosive cyclogenesis-the scientific term for the phenomenon-the system must exhibit a drop in atmospheric pressure of at least 24 hPa (millibars) over a 24-hour period. “Millibars are the unit of measurement used for atmospheric pressure,” explains Professor Cecchini, who receives support from the Serrapilheira Institute. Because atmospheric pressure is lower and the temperature difference between the air masses is more pronounced when a bomb cyclone forms, storms develop along the boundary between them. “The cold air mass pushes beneath the warm air mass because it is denser, causing the warm air to rise. This upward movement forms clouds and storms. If the temperature difference is large, this updraft will be more intense,” he explained. Intensity The result is more intense storms, with lightning and the possibility of hail. According to the National Institute of Meteorology (INMET), if the forecast holds true, this is expected to occur from Thursday (6) through Saturday (8). Satellite images indicate that the strongest winds will occur mainly over the Atlantic Ocean, where speeds may exceed 100 kilometers per hour. Along the coasts of the states of Rio Grande do Sul and Santa Catarina, wind gusts exceeding 60 km/h are forecast. As the cyclone moves southeast toward the Atlantic Ocean and away from the coast, an associated cold front is likely to advance across Argentina and southern Brazil.