Numeric experiments were run with meteorological regional model with the purpose to verify the impact of both latent and sensible surface heat fluxes (FCL and FCS, respectively) during the development of an intense east cost cyclone over southeastern region of South America from 24 to 26 July, 1998. The intensification rate of the cyclone was reduced by 6 hPa/24 h in the experiment where the FCL and FCS were absents. It was also verified that the absence of FCL presented more impact than without FCS. The intensification rate was reduced by 6 hPa/24h in the experiment without FCL and became unaltered in the experiment without FCS, but in the later the isobar with minimum value around the cyclone center occupied a smaller area. The absence of the FCL and FCS generated a drier and colder layer near the oceanic surface, reducing the environmental potential instability and decreasing the cyclone intensification. With these results it is possible to conclude that the FCL and FCS were important before the phase of most rapid cyclone development, preparing the environment to a more intense cyclogenesis, supplying both energy and moisture to the lower troposphere. In the phase of the most rapid development, the available energy and moisture (inserted in the previous phase) in the lower levels were also important, allowing the cyclone to develop more intensely than it could be in a drier and less thermically unstable environment.
cyclogenesis; surface heat flux; regional model
