Quase-Linear Convective Systems Over Complex Terrain in South of Brazil

The South Region of Brazil (SRB) is frequently hit by severe storms that organize like

narrow and elongated lines of severe convection, known as Quasi-Linear Convective Systems (QLCS),

in particular due to equivalent potential temperature gradients, vertical shear and Convective

Available Potential Energy presents in the environments. In Addition, part of the SRB has a very

complex terrain, especially over the east coast, where slopes of more than 1500 meters are present.

The QLCS propagates eastward and interact with terrain barriers up to 1500 meters and in some cases

cross the highest region and reach the coast to the east. In the warm seasons this is more common,

since the QLCS are more frequently. In this work 5 years of radar data are analyzed with a focus on

identifying QLCS over the region of complex terrain. This analysis show that the QLCS are more

frequently in spring season especially on October month. The first year analyzed (2015) indicates

a highest number of cases, in contrast with 2019-fewer cases. The cases are analyzed using observation

and severe weather reports with the aim of highlight potential influence of terrain in structure and

severity of SLs. All cases occurred in warm season, and propagates predominantly eastward.