This case study shows a non-frontal situation where a distinct upper level feature, namely an upper level trough and jet streak producing PVA and cloudiness, crosses a completely different feature of a convergence band with some instability embedded. This mergence leads to a highly unstable troposphere and the development of intensive thunderstorms.

The model was very well able to diagnose and forecast the situation as a whole. But as expected, it was not able to forecast the location of single thunderstorm developments. For this purpose only methods used for nowcasting are appropriate tools at the present time.