Malguzzi, Piero (FISBAT-CNR, Bologna, Italy)
Buzzi, Andrea (same affiliation)
Tartaglione, Nazario (same affiliation)
In the context of the ANOMALIA EU project, a number of cases of heavy precipitation, occurred recently in the western Mediterranean area, have been studied. In most of these cases, a strong orographic influence is found, while in all cases humid processes, associated with condensation and evaporation/melting of precipitation, have a strong dynamical feedback on mesoscale structures. We consider here in particular two events (the Brig flood of Sept. 1993 and the Piedmont flood of Nov. 1994) that exhibit interesting analogies in terms of synoptic scale situation and of mesoscale features over the Mediterranean. In both cases frontal splitting, associated with the formation of convective rainbands, is observed and studied numerically in order to understand the onset and maintenance of such structures, which seem to have played an important role for the localization of the strong precipitation. The role of evaporative cooling has emerged as a primary effect to maintain the multiple band structure.