Tropical Cyclone Dynamics

**27**

48o

**1. Introduction**

and Salvador, Bahia state (13o

fog formation in Maceio, Alagoas State (9o

W), and Quixeramobim, Ceara State (5<sup>o</sup>

**Chapter 2**

**Abstract**

Impacts of Tropical Cyclones

Adverse Phenomena Formation in

Tropical cyclone (TC) impacts on adverse phenomena in the tropical region of Northeastern Brazil (NEB) have been analyzed. TC influence on fog and rain formation was not described in the previous papers. The main goal of the chapter is to evaluate the existence of such influence and thus to improve the weather forecasting in this area. TC information from the NHC of the NOAA was used. METAR and SYNOP data were used for the adverse phenomena study. Analysis of the synoptic systems was based on different maps at the pattern levels and on satellite images. These maps were elaborated using reanalysis data from the ECMWF. Thermodynamic analysis was also used. Middle tropospheric cyclonic vortexes (MTCV) in the tropical region of the Southern Atlantic were described recently. Five from 10 MTCVs were associated with tropical cyclones and disturbances in the Northern Atlantic. Circulation patterns between TC and synoptic systems at the NEB are described. These circulations create sinking over the BNE and, as a result, form fog, mist and weak rain in the BNE during TC days. Mechanisms of TC influence on weather formation in the BNE are presented. This information is

in the Northern Atlantic on

Northeastern Brazil

*Natalia Fedorova, Vladimir Levit* 

*and Lucas Carvalho Vieira Cavalcante*

important for improving weather forecasting methods.

**Keywords:** tropical cyclones, Northeast Brazil, adverse phenomena

S, 39o

Fog and mist events are rare and show significant variation of frequency in the tropical region of the Brazilian Northeast (BNE) [1, 2]. Radiosonde data in the central and south regions of the BNE, i.e., Recife, Pernambuco state (8o

and 37 (41) days per year, respectively [3]. On the other hand, in the first study of

erate and weak) during 1996 (both in winter) were found. Fog does not exist in the semiarid region [3]. In the northern region of the BNE, i.e., Belem, Para State (1o

S, 39o

S, 39o

S, 35o

W), registered fog (haze) on average in 13 (13)

W) [4], only two fog events (mod-

W), fog (haze) was registered in

W),

S,

## **Chapter 2**
