Characteristics of Cold Fronts Causing Heavy Rainfall Over Eastern Santa Catarina

Abstract This article analyze the main characteristics of cold fronts yielding heavy rains on the coast of the State of Santa Catarina with the further purpose of improving its knowledge and prediction. A synoptic climatology was performed using NCEP CFSR reanalyzes and CPTEC/INPE precipitation data for the1998-2010 period, considering 5% of the wettest cases. Results showed that cold fronts causing heaviest precipitation have a rather uniform temporal distribution along the year, associated with strong, cold and rather barotropic troughs at middle and upper levels. The slow meteorological evolution allows a progressive low-level trough deepening that increase temperature and moist advection from the Amazon to eastern Santa Catarina thus intensifying thermodynamic instability. The cold front that triggers precipitation has strong low-level tilt and slow movement. Atmospheric conditions linked to frontal passages causing heavier precipitation have minor seasonal variability and can be detected at least 48 hours in advance.