29th May 2005: 00UTC
In the image the frontal system can be recognised. It is superimposed with warm air advection. Further north the cold air advection behind the occlusion is also pronounced and nicely visible. Ahead of the frontal system an area with WA is seen over Switzerland and Austria. This in combination with the drier and colder air at upper levels (see "WV6.2 29-5-2005 00UTC") leads to potentially unstable stratification of the troposphere.
29th May 2005: 06UTC
29th May 2005: 12UTC
In the warm sector ahead of the front, previously discussed, some convective cells emerged. Over the Jura and the Vosges mountains some separate cells have emerged. Further to the east over Turkey also warm air advection prevails which will slightly contribute to the updrafts found in the convective cells.
29th May 2005: 18UTC
The situation over Turkey has remained unchanged. WA is still dominating. Some of the convective cells have reached a mature stage and are dying out. The convective appearance over Greece and Turkey has diminshed. More interesting is the pronounced WA maximum found in the frontal band over Belgium. The area is likely to show some convection in the next few hours.
30th May 2005: 00UTC
30th May 2005: 06UTC
30th May 2005: 12UTC
At this timestep the large convective event over Central Europe is about to start. Most of the area found at the leading edge of the front is characterised by CA. Some cells are already seen and marked here by a red '+' (Czech Republic, Adriatic coast) which indicates small WA maxima that will slightly contribute to the upward motion and indicate the maximum of positive thermal advection.
30th May 2005: 18UTC
The region of interest is still characterised by CA. A larger maxima of CA is seen embedded into the frontal system. Only at the leading edge some WA maxima are seen which correspond to the cold cloud tops seen in IR imagery. The WA maxima may contribute a little to the further development of thunderstorms.
