Since the 1999, experts of ISTI (an Institute of the Italian National Research Council) collaborate with ASI (the Italian Space Agency) on the flight dynamic of the Stratospheric Balloons (pre-operation and operation activities included). The latest developments on Subsystems and methodologies for flight prediction will be discussed. The Atmospheric Forecast data are very important for the stratospheric balloon trajectory prediction. The received data permits a 48-72 hours of wind prediction. This data are meshed with measured information coming from soundings and/or gps few hours before flight or during it. The average errors on the wind status are evaluated for a statistical analysis of the flight areas. The error evaluation on the vertical velocity's prediction is made too. Taking into account all the variables, it is possible to define (on ground) a path, with high and low probability of landing areas. The path is superimposed onto cartography and the real trajectory display, for an operational use. Sounding data, collected few hours before the flight or during it, are able to reduce the path's dispersion. The prediction software must communicate with the monitoring and control software without reducing its stability and/or performance