Severe convection and lightning in subtropical South America

Rasmussen, K. L., M. D. Zuluaga, and R. Houze (2014), Severe convection and lightning in subtropical South America, Geophys. Res. Lett., 41, 7359-7366, doi:10.1002/2014GL061767.

Satellite radar and radiometer data show that subtropical South America has the world’s deepest convective storms, robust mesoscale convective systems, and very frequent large hail. We determine severe weather characteristics for the most intense precipitation features seen by satellite in this region. In summer, hail and lightning concentrate over the foothills of western Argentina. Lightning has a nocturnal maximum associated with storms having deep and mesoscale convective echoes. In spring, lightning is maximum to the east in association with storms having mesoscale structure. A tornado alley is over the Pampas, in central Argentina, distant from the maximum hail occurrence, in association with extreme storms. In summer, flash floods occur over the Andes foothills associated with storms having deep convective cores. In spring, slow-rise floods occur over the plains with storms of mesoscale dimension. This characterization of high-impact weather in South America provides crucial information for socioeconomic implications and public safety.

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