Influence of Tropical Disturbances on Severe weather phenomena of Stable Atmosphere Formation in Northeast Brazil

Abstract

The main aim of this study is to analyze an impact of Tropical Disturbs (TD) in the Northern Hemisphere (NH), associated with Tropical Cyclones (TC), on adverse phenomena in Northeast Brazil (NEB) in 2013 - 2015, in order to improve the weather forecasting method in this area. Information about TC was obtained from the National Hurricane Center. Adverse phenomena were studied using METAR and SYNOP data. The synoptic analysis was based on the satellite images and maps of different variables. Reanalysis data from the European Center for Medium-Range Weather Forecasts were used. Nine TD were observed during the passage of TC. In the same period, fogs and mist with drizzle were recorded in the NEB. These phenomena were associated with the trough in the NEB created under the influence of TD in HN. The current from TD in NH converges with current from extratropical cyclone trough of the Southern Hemisphere at the high levels over the NEB. This convergence created sinking, contributed to the accumulation of moisture at the low levels and the formation of adverse phenomena. The results confirm the effect of TD in NH on the weather at the NEB and important for weather forecast in this region.

Keywords:
tropical disturb; severe weather phenomena; Northeast Brazil