The algorithm for very-short term precipitation forecasting (Berenguer et al., 2005; 2011) is based on the extrapolation of radar precipitation observations according to the estimated motion. The algorithm is composed of two different modules for:
• Precipitation tracking: the tracking algorithm estimates the motion field with a given resolution based on the analysis of 2 or 3 consecutive radar maps, based on a modified version of COTREC (Li et al., 1995).
• Extrapolation: precipitation nowcasts are obtained by linearly extrapolating the most recent radar precipitation map in time according to the retrieved motion field.
Two different versions of the nowcasting algorithm will be implemented: a deterministic version, and a probabilistic version (based on SBMcast; Berenguer et al., 2011). The latter is an ensemble nowcasting approach that generates precipitation scenarios compatible with the most recent radar observations and that respects the space-time structure of the precipitation field and its motion.