PVA at 500 hPa was connected to the cold front as well as to the cellular cloudiness behind the front.
24 Nov 2005, 06 UTC
Unlike the situation in 300 hPa a pronounced maximum of PVA in 500 hPa was also connected with the comma at this time.
24 Nov 2005, 12 UTC
During the merging process the maximum of PVA overrided the frontal band. That corresponds much better to the conceptual model of an instant occlusion than the model fields at 300 hPa.
24 Nov 2005, 18 UTC
At 18 UTC only one maximum can be found near the Dutch coast.
25 Nov 2005, 00 UTC
The maxima of PVA were less pronounced at this time and only connected with the southern part of the cold front. The comma which has now merged with the cold front cloud band is not superimposed by PVA in 300 hPa.
25 Nov 2005, 06 UTC
Low maxima of PVA were connected with some parts of the cloud spiral. The main reason for the high extending clouds was the intense warm air advection in this region.
25 Nov 2005, 12 UTC
Weak PVA was connected with some parts of the cloud spiral. The compact cloud band was related to intense warm air advection.
25 Nov 2005, 18 UTC
The general situation did not change significantly. All features (weak PVA-maxima and cloud band) moved slightly to the West.
26 Nov 2005, 00 UTC
Negligible maxima of PVA happened at the end of the time period.
