26 May 2006: 12 UTC

The VCS was laid from position A to B.

Isentropes

The isentropes show a configuration typical for a pronounced thickness ridge in front of the cold front.
Almost constant values of equivalent potential temperature can be seen up to 600 hPa in the area where the high convection within the cold front takes place. The similar configuration is found further to the south-east where is extends up to 500 hPa. That is the  position of the prefrontal convergence zone characteristic for an unstable atmosphere.