Environmental Characteristics Associated with the Tropical Transition of Mediterranean Cyclones

Abstract. Cyclonic perturbations in the Mediterranean region sometimes acquire characteristics typical of tropical cyclones, such as a deep inner warm core. In these cases, they become very intense structures that can cause large precipitations and significant damage. In this study, the environmental conditions during the intensification of cyclones are investigated using reanalysis data. A comparison of the conditions associated with the evolution of classical and intense cold-core extratropical cyclones and those associated with the development of tropical-like disturbances highlights the characteristic that favors the conversion: a much larger potential intensity and a weaker vertical wind shear. The larger potential intensity associated with Mediterranean tropical-like cyclones comes from both higher SST and a strong PV-intrusion that destabilizes the air column. Sea surface cooling induced by the cyclones is further shown to play a role in the dissipation of tropical-like cyclones. Future research should focus on the role of potential intensity as a precursor for Mediterranean tropical-like cyclone forecasting, improving predictive capabilities and risk mitigation strategies in the Mediterranean region.