A subsynoptic vortex over the Mediterranean with some resemblance to polar lows

Abstract

The development of a subsynoptic vortex over the Mediterranean has been followed for several days (27 September‐1 October 1983). The major tool for the study are METEOSAT images from the visible and infrared spectrum, and wind data from low and high levels obtained by tracking cloud elements in these images. The subsynoptic vortex forms in the central part of a synoptic scale low of modest intensity, and deep convection is observed in the region prior to the formation of the vortex. The initial formation of the vortex is most probably caused by a rapid spin‐up due to intense convection of pre‐existing vorticity associated with the synoptic scale low. After its formation, the vortex moves in a large circle and is best developed at a position over the sea west of Sardinia and Corsica. The vortex at this time is characterized by deep convection, a vertical axis and an upper‐level anticyclonic divergent flow corresponding to a warm core structure.

Development and Tropical Transition of an Alpine Lee Cyclone. Part I: Case Analysis and Evaluation of Numerical Guidance

“…This development pathway is closely linked to ''cold low'' cyclogenesis described by Businger and Reed (1989). The existence of hurricane-like features in the region is also studied by Ernst and Matson (1983), Mayengon (1984), Rasmussen and Zick (1987), Pytharoulis et al (2000), Reale and Atlas (2001), and Moscatello et al (2008). Because these systems generally form under conditions of upper-level troughing not normally considered conducive to tropical cyclogenesis, the potential of their conversion to tropical vortices following a tropical transition (TT; Davis and Bosart 2004) pathway represents an important aspect of their life cycles.…”

Medicane risk in a changing climate

“…Tropical‐like cyclones of a few hundreds of kilometers in diameter occasionally evolve over the Mediterranean Sea [ Ernst and Matson , ; Rasmussen and Zick , ; Reale and Atlas , ], posing a serious threat to any densely populated area found in the vicinity of their tracks. These storms have captured the attention of the research community and have been called medicanes (see Figure for an example).…”

Mediterranean Tropical-Like Cyclones in Present and Future Climate

“…It has been suggested that the increased sea surface temperature in an anthropogenically warmed climate could lead to favorable conditions for the formation of hurricanes in the Mediterranean Sea (Gaertner et al 2007). After the advent of satellite meteorology in the last decades of the twentieth century, on the other hand, evidence emerged (Ernst and Matson 1983;Rasmussen and Zick 1987) indicating that a few mesoscale vortices showing a striking resemblance to tropical latitude hurricanes occasionally do occur over the Mediterranean Sea. Such storms exhibit a cloud structure characterized by a central eye surrounded by spiral-shaped cloud bands, and the strong winds associated can reach hurricane strength; the most intense storms of this kind have thus been termed Mediterranean hurricanes (medicanes).…”