Tornado and hail records in Italy on 22 and 24 July 2023

Two relevant events occurred during the extreme severe storm outbreaks on July 2023 were studied: the IF3 Alfonsine tornado on 22 July2023 and the record-breaking hailstorms in the Friuli Venezia Giulia (FVG) region on 24 July 2023. The tornado path was reconstructed by PRETEMP, a volounteer group of students and meteorologists, thanks to many surveys conductedby some amateurs. The tornado path was 16.7 km long and up to 1.3 km wide, resulting in the largest tornado documented in Italy untilnow. Observations (weather stations and radar images) revealed that the tornado developed when a supercell crossed a triple point, i.e., aregion of convergence between northerly outflows, a very moist easterly flow, and a dry southwesterly flow. The extreme hailstorms on 24 July 2023 were analysed using the radar of Fossalon di Grado, managed by the Civil Protection of the FVGregion. The storms were characterized by an impressive Bounded Weak Echo region in the reflectivity field, and by a couplet of inboundand outbound velocities in the medium level, highlighting the presence of a mesocyclone. Atmospheric soundings showed that theconvective potential instability measured just before the development of the hailstorms was quite low, while the vertical wind shear and thestorm relative helicity were very strong. We hypothesized that the strong flow and the large amount of moisture in the 1-3 km layer abovethe ground level were crucial for the generation of the extreme hailstorms, while high CAPE was not essential. Finally, Numerical Weather Prediction (NWP) models were able to simulate already two days ahead the development of the supercells inboth events, permitting accurate severe storm forecasts.