Studying Physical Mechanisms of Development of Black Sea Quasi-tropical Cyclones Using a High-resolution Atmosphere Model

High-resolution modeling is implemented to investigate an evolution of two quasi-tropical cyclones (QTC) over the Black Sea: in September of 2005 and 2018. For comparison, the quasi-tropical hurricane Zorba, that developed over the Mediterranean Sea at the end of September 2018, is considered. An assessment of factors leading to the origination and intensification of QTCs is carried out, and the predictability of the phenomenon is studied. The authors tried to reduce the analysis to the parameters obtained directly as a result of mesoscale nonhydrostatic modeling. In all the considered cases, the period of active development of cyclones was preceded by the formation of a core of warm air above the sea surface; the moisture inflow from the lateral boundaries was more important in the moisture balance. It is found that coarser spatial resolution predictions are more successful for large QTCs.