Preliminary Survey of Extreme Weather Events in Southern Brazil

Recent studies have shown that over the southern Brazilian Region, specially over Santa Catarina and Rio Grande do Sul States, there is an increase in the number and frequency of extreme weather events. This climatic behavior of the precipitation depends on the meteorological phenomena that act directly in the region, besides the topography and the geographical position of the State. The goal of this study is to carry out a preliminary survey of the extreme weather episodes related to precipitation over the Santa Catarina State (CS) from 2012 to 2016. A selection of cases was performed using the monthly monitoring system maintained by CPTEC based on two criteria: phenomena associated with the storm with records of occurrence of hail, strong winds, tornadoes and/or microexplosions; Intense precipitation (> 50 mm) and/or precipitations with significant volume over a period of time. From the selection of the cases, a synoptic analysis and spatial distribution of each of the systems that caused the events of extreme precipitation phenomena was performed. During the study period, 93 cases of events associated with the occurrence of extreme events in CS were recorded. The atmospheric systems prevailing on days when there was extreme event registration in CS were: cold front, High Level Cyclonic Vortice, sea circulation, low pressure, cyclone, trough and thermodynamic process. The passage of cold fronts was responsible for 27 of the total cases, being the predominant system associated with extreme events related to precipitation in the CS.