This case study showed a frontal system moving from south Scandinavia over central Europe to south Adriatic with several intensifications in the left exit region of the Jet streak. The cold front was propagating on the leading side of the pronounced upper level ridge and intensive precipitation was reported in the whole area of the cloud intensification. During the time the upper level trough became deeper with axis from Finland over east Europe to the south Adriatic.
In the satellite images the intensified cloud bulge could clearly be seen. At one point the intensification split in two parts, which was also observed in the relevant parameters. In the WV channel the intrusion of the cold and dry air can be seen in form of dark areas, and the location of the jet in these images can be followed by looking at the dark stripes. The cold advection can be seen in both IR and WV images, and the combination of the channels (RGB 139) enables us to look at clouds in the different heights.
The field of isotachs and PVA showed a strong maxima in the region of intensification which is in good relation with the satellite images of the clouds in the different channels. Following the theoretical model, the strongest maximum of the Positive vorticity advection was found in the left exit region of the jet streak and it was placed directly above the intensified cloud bulge.
Besides the main process of frontal intensification there were also some small scale processes that went on, like forming of a comma cloud structure over Hungary and in the end another one over south Adriatic. Both processes were also connected to the vorticity advection.