Estudo de um evento de chuva intensa acontecido no município de Pelotas, RS, em janeiro de 2009

Abstract

The main objective of this study was to analyze the synoptic conditions and to evaluate the WRF model forecasts using different parameterizations of cloud microphysics of the extreme rainfall event in the municipality of Pelotas, RS, in January 28th, 2009. Synoptic analysis demonstrated that the main factors for occurrence of intense rains were strong convergence of wind in low levels and upward vertical movements, as well as a strong moisture flux convergence in lower levels, which were essential ingredients for the occurrence of precipitations. Advections of temperature and vorticity were practically null throughout the period of formation and intensification of the extratropical cyclone. WRF forecasts did not consistently represent the location and intensity of the event for 12, 24, 48 and 72 hours in advance. The forecast made 12 hours prior the beginning of precipitation presented higher accumulated rainfall in the region of the municipality of Pelotas, but with intensity much lower than observed.