As shown below the appearance of a Comma in a vertical cross section is best described by a cross section taken south of the Comma head. One of the most characteristic properties of Commas is the instability in lower and middle levels. The unstable airmass is indicated by the distribution of the isentropes up to 800 - 700 hPa. In most cases no frontal character can be seen in the lower troposphere, but in upper levels (above 500 or 600 hPa) sometimes one can see a downward inclination of the isentropes forming a higher gradient. The peak belonging to the Comma feature under consideration is the one in the middle of the cross section (49.5N/22.5 - 24W). The more western peaks belong to convective areas in the centre of the Comma spiral.

Commas exist in areas of positive relative vorticity throughout the whole vertical cross section. The maximum is at the rear side at about 400 hPa (never below 500 hPa and not higher than 300 hPa).

Vertical cross sections show PVA above the cloudy area with its maximum in the upper troposphere in advance of the corresponding vorticity maximum. Both behind and in front of the Comma there can be PVA, but also NVA. Commas are often associated with upward motions throughout the whole atmosphere. The profile of temperature advection shows cold advection over the cloudy area, sometimes also in front of it. The vertical distribution of divergence shows convergence in lower levels often decreasing with height; that can result in divergence in upper levels. This is consistent with upwards motion (see above). Convergence is generally found near the cloudy area but may sometimes be present in the surrounding areas. Convergence is occurring in this case is in thick layer from the surface up to 700 hPa.