This study presents the methodologies used to develop a nowcasting system of Mesoscale Convective Systems (MCSs) over the Mediterranean region on the basis of Meteosat Second Generation (MSG) imagery. The nowcasting system is an algorithm that detects and tracks MCSs in Meteosat images and then forecasts the movement and the evolution of the physical properties of a selected MCS through its entire lifecycle, at 15 min intervals. The forecasting procedure combines a linear extrapolation method of the MCS life cycle history and information extracted from conceptual models. As a final output, the system generates a complete life cycle forecast of the temporal evolution of several physical characteristics of the MCS, such as areal extent, displacement, mean brightness temperature and convective potential, and visualizes the forecast by drawing ellipses that represent the MCS with 15 min time steps. Forecasts of a complete life cycle are updated every 15 min in accordance to the acquisition of a new satellite image.