Vertical Cross Section: 30 July 2005:06UTC

Isentropes
The isentropes show a configuration typical for a system with a pronounced thickness ridge in front of the cold front. The coldfront part in the isentropes shows two phenomena:

1. A downward inclined zone of high gradient as it is necessary for a frontal surface.
2. A bulge close in lower layers which is characteristic for a highly unstable situation.

The VCS was laid from position A to B. Click the image to enlarge.

Temperature Advection
The Temperature Advection shows a typical distribution of a cold front. Within the front cold air advection dominates. Ahead of the frontal zone an area of warm air advection is found near the surface in the region that is charaterised as unstable. The warm air advection may slightly contribute to rising motions.

Convergence
The field of convergence and divergence show a double structure. The cold front part is accompanied by a (backward inclined) zone of convergence. But there is also a second pronounced maximum of convergence found in the lower layers ahead of the front. This corresponds with the pronounced positive temperature advection and the unstable stratification of the equivalent potential temperature.

Vertical Motion (Omega)
Less distinct as one would expect but the most rising motions are in accordance with the unstable stratification ahead of the cold front. This is the region where at a later stage the convection will start.