Synoptic and thermodynamic analysis of thunderstorms events in the Alagoas State, the Northeast Brazil

Abstract

Synoptic and thermodynamic analysis of 14 thunderstorm events in the Alagoas State (Northern Brazil) was elaborated. Thermodynamic analysis was based on the vertical profiles, forecasted with 48 hours in advance. Forecast was made by the air parcel trajectories from the HYSPLIT model in 10 standard levels. Instability indexes were applied in order to better evaluate the quality of the vertical profiles. It was considered the topography influences on the intensification of the thunderstorms. That was made by evaluation of the Potential and Latent Instabilities (IP and IL), for each case. An analysis of two events on April 6, 2014 was presented in details. The following data were used: (1) Brazilian Meteorological Department (REDEMET); (2) Tropical Rainfall Measuring Mission (TRMM); (3) Reanalysis data from The European Centre for Medium-Range Weather Forecasts (ECMWF) and (4) National Centers for Environmental Prediction (NCEP); Sounding and GOES and METEOSAT satellite images from (5) Brazilian Forecast and Climate Study Center (CPTEC); (6) HYSPLIT model; (7) The Environment and Water Resources Department of Alagoas (SEMARH); (8) Planning and Economic Developing Department of Alagoas (SEPLANDE), The Forecasted profiles were satisfactory up to 48h in advance. The IP and IL were responsible for an increase of the CAPE+ of 2.7 times. It was identified an influence of the ITCZ, which was located to the South of the climatological location, because of a cold front nearby. Strong trough over the South Atlantic at the high levels was associated with the thunderstorm development.