Convergence is of course a prominent feature within the frontal circulation leading to frontal cloud bands. However there are cloud configurations, mostly in band form which do not show frontal characteristics but appear in zones of convergence which can occur in any layer of the troposphere. Cloud configurations vary according to the depth and height of the convergence layer.

There are different synoptic environments where such Convergence Bands are often observed:

• together with Upper Level Lows (see Upper Level Low ) mostly in the developing stages of a cut-off process
• as a mesoscale cloud band with smooth but low cloud tops, with convergence in a low layer, often over the North Sea
• in connection with Occlusion cloud bands on the north-western side of the cloud spiral where different air masses converge
• in connection with a sequence of Occlusion cloud bands where different air masses converge
• Convergence Cloudiness also develops in coastal areas over extended lakes due to friction differences between water and land. Mostly visible as a line of Cu or Cbs over sea near the coast. All under the specific unstable condition where wind direction is within a certain angle to the coast line.

The best tool for a confirmation of such a development background are vertical cross sections of convergence. In most cases isentropes which show a non-frontal configuration are superimposed by a layer of convergence with vertical motion above. If these convergence zones exist at higher levels there might even be sinking below.

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