1. Professor, Dept. of Meteorology, Federal Univ. of Pelotas, Campus Universitario Cx. Postal 354, CEP 96010-900, Pelotas, RS, Brazil (corresponding author).
2. Researcher, Parana Meteorological System (SIMEPAR), Francisco H. dos Santos 210, CEP 81531-980, Curitiba, PR, Brazil.
3. Student, Parana Meteorological System (SIMEPAR), Francisco H. dos Santos 210, CEP 81531-980, Curitiba, PR, Brazil.
4. Researcher, Meteorological Research Institute, Sao Paulo State Univ. (IPMET/UNESP), Eng. Luiz Edmundo Coube, CEP 17033-360, Bauru, SP, Brazil.
5. Researcher, Center for Weather Forecasting and Climate Research (CPTEC/INPE), Presidente Dutra Highway, km 39, CEP 12630-000, Cachoeira Paulista, SP, Brazil.