**Abstract**

Heavy rainfall and strong winds occurred in the South of Mato Grosso do Sul State, Brazil on 5 December 2015. In this study the synoptic conditions responsible for the storms and their social consequences are analyzed. Also, the state-of-art model (WRF) was used to simulate the atmospheric conditions in this severe event. The results showed that the storm had harmful consequences both in the cities of the region and in the interior of the state, with floods, threw down trees and impacts on the energy distribution. The synoptic analysis showed that over the Mato Grosso do Sul State at high levels occurred a region of wind difluence which was associated with convective clouds of large vertical development. This event was responsible for the heavy rainfall and strong winds in the region. The model results showed that the simulations were in good agreement with the observations. Thus, numerical weather forecast using the model may be extremely useful to obtain important information to mitigate the possible adverse effects of future severe weather events. This study forms part of a cooperative Project between National Institute for Space Research and Energy Power Company aimed to mitigate the impacts of severe events.

**Keywords:** heavy rainfall in Mato Grosso do Sul state, Brazil, impact of severe weather conditions, numerical model simulation
