Characterization of synoptic systems triggering disasters in the state of Espírito Santo, Brazil

Despite the extensive research about hydrometeorological disasters in southern Brazil, only a small portion focuses on the state of Espírito Santo (ES). This state is frequently affected by such disasters. Therefore, this study aims to identify and characterize the synoptic systems responsible for heavy rainfall events that lead to disasters in ES. To achieve this, we analyzed disaster events from 2013 to 2021 using data from the S2ID database, CPTEC synoptic charts, GOES-13 and GOES-16 satellite imagery, and INMET precipitation records to determine the dates and characterize the meteorological conditions associated with each event. Additionally, ERA5 reanalysis data were used to generate composite maps. The research findings indicate that disasters affecting ES occur primarily during the summer, consistent with a thermodynamically more unstable atmosphere. The main synoptic patterns identified are as follows: 1- Intense frontal systems that disrupt pre-existing blocking situations in the preceding days, facilitating the advection of humid air from the Atlantic Ocean.; 2- The South Atlantic Convergence Zone (SACZ) associated with a anomalously warm anticyclone over the Atlantic and an intense low-pressure center to the north, also exhibiting a blocking pattern; 3- Troughs with slow displacement and low baroclinicity associated with high convective instability, acting as an extension of the Chaco Low and Thermo-Orographic Low, and 4- Cold core cyclones with barotropic characteristics, located over ES, linked to warm blocking anticyclones, positioned south of approximately 40–45° S. These patterns were detectable at least 48 h in advance, highlighting their potential for early warning systems.