Mesocyclone characteristics in Romania

Rotating storms do occur in Romania and some of them produce tornadoes, strong winds, flash floods and severe hail. Romanian forecasters are challenged to recognize environmental mesoscale factors that favor the onset of supercellular thunderstorms, mainly in southeastern Romania, where the environment tends to be more conducive to severe convection than in other parts of the country. Observations of storms whose buoyant updraft contains air originated in the boundary layer often shows that they are initiated along or near surface airstream boundaries. Mesoscale lift along such surface boundaries can decrease the convective inhibition, increase the convective available potential energy, and moisten the air column. Surface boundaries are also an important source for low-level shear that can favor or enhance the development of mesocyclonic storms. In this paper, the mesoscale patterns and the conceptual models of the features which favored development of surface boundaries connected with mesocyclones are analyzed. The aim of this approach is to establish connections between quantitative characteristics of the environment, lifting mechanisms and mesocyclone intensities, dimensions, and life cycle in Romania as detected by Doppler S band radar, developing a radar climatology for different mesoscale patterns.