An operational approach to the nowcasting of an intense thunderstorm over Liguria

Abstract. In the period between late spring and early summer as well as in autumn, the Mediterranean is often affected by rapid development of intense convective systems. In some cases the operational NWP models are able to provide good indication of occurrence of such severe weather events (potential instability conditions) but often location and intensity of convective precipitation are poorly forecasted.

The approach of "PV-thinking" revealed itself as a good tool to identify favorable conditions for triggering such systems, partially filling this lack of information and supporting meteorologists in the very short range weather forecast. Moreover, the advanced use of data provided by SEVIRI channels onboard MSG satellite, makes possible an effective application of the PV approach, improving forecast skill also in areas where local effects are not well described by the models and/or by the data assimilation. The aim of this work is to show how the application of the MSG tools together with the PV philosophy helps in the diagnosis and nowcasting of intense thunderstorms triggered by tropopause, with particular attention to a case of intense convection over northwestern Italy during spring 2005.