Analysis of the Most Intense Explosive Cyclone that Occurred Between 2010 and 2020 in the South Atlantic

Abstract

The coastal region of South America is known for the high frequency of extratropical cyclones. From 2010 to 2020, there was an exceptional case regarding intensity, reaching 2.73 Bergeron, between January 02 and 03, 2019. To better understand the characteristics of this type of explosive cyclone, this work sought to investigate the synoptic conditions in this phenomenon. To this end, a visual inspection method of the sea level pressure charts was applied, allied with the functions available in the Grid Analysis and Display software. The cyclone began by transitioning from the continental low to the extratropical cyclone, associated with a trough at higher levels in a zone of weak temperature advection. As the system developed, there was a fracture in the upper air trough, acquiring negative horizontal inclination and the transition of the cyclone from the tropical to the polar side of the jet streak. Sea heat fluxes become relevant only 6 hours after cyclogenesis and enhance as the surface wind increases in the cold sector of the cyclone. In addition, a robust stratospheric ozone intrusion arose close to 700 hPa in the cyclone region, related to the dynamic tropopause folding.