EUMeTrain: Series of convective developments over Turkey on 26th of May 2006

Summary

The case study describes the series of convective developments within and in front of a cold front moving over Turkey from the north-west further to the east.
The first development was noticed over Romania at the leading edge of the front during the 25th May. Very soon the convective development started ahead of the front induced by orography over Greece, and during the night over Turkey, near Ankara. Explosive development over Turkey during the 26th is nicely depicted in the set of radar-images, but unfortunately the weather bulletins were not available. The second convective development during the 26th was observed over Eastern Turkey caused by the upper level low, later merged with frontal cloudiness.
Convective events of this days were investigated using different sets of Meteosat 8 satellite images and RGB composites. In all types of satellite images used in the analysis, severe convective development was well witnessed.
The analysis of the enhanced infrared images showed cloud tops with brightness temperature of around -70 °C. Convective cells developed on the WV boundary which is, in theory, a preferred location for the deep convection. Severe convection was also studied by the RGB composites which enable a detailed look into the structure and life cycle of the convective cells.
Convective development was also investigated by numerical fields of basic and derived parameters. The atmosphere was unstable, as seen in stability indices and the equivalent potential temperature at 850 hPa. The area of maximum convection fits well with negative values of the Showalter index and maximum in ThetaE 850 hPa fields. Downward protruding stratospheric air is also documented by model fields of potential vorticity at 300 hPa.
The vertical structure of the atmosphere during the 26th was investigated by vertical cross sections.