Mean synoptic-scale conditions accompanying convective storms that produce hazardous weather phenomena in southern Brazil (SB) and neighboring areas are investigated. Emphasis is placed on discriminating between conditions conducive to tornadoes (TORN) and those to heavy rainfall (RAIN) and non-tornadic wind gusts (GUST). For this purpose, an analysis of the meteorological conditions associated with 40 events from each severe weather category is conducted using data from CFSR/CFSv2 reanalysis. Data are sampled for times closest to the severe weather event in a 30 \(^{\circ }\times 30^{\circ }\) adaptive latitude-longitude domain centered on each event location. Average charts are obtained for the synoptic fields and atmospheric parameters, and mean tropospheric profiles are compared among the distinct hazards. Overall, the role played by a surface low pressure system that extends to SB is highlighted, conditioning the environment to convective storms. This system favors low-level northwesterly moist flow and surface convergence over the center of the domain. Subtle differences are found between the TORN and GUST composites, with the former exhibiting weaker baroclinic forcing but stronger vertical wind shear in the lower troposphere. Distinctions between TORN and RAIN are more pronounced, with TORN exhibiting more intense horizontal pressure gradients, surface-based CAPE, and vertical wind shear. The average wind profile for TORN exhibited the most elongated and curved hodograph at low levels. Convective parameters showed poor discrimination between TORN and GUST, while performing better in discriminating TORN from RAIN, especially the shear parameters computed along the effective inflow layer of the storms.
