Ik vond dit op stratusdeck.co.uk :
Within the front itself, it is important to note the flow of air relative to the movement of the frontal surface. This can impact the positioning of the cloud band and the intensity of the precipitation. In an Ana front, the warm air moves up the frontal surface, generating thick clouds and heavy precipitation. There is a greater potential for convective clouds in this case. In contrast, in a Kata front, the warm air moves down the frontal surface, supressing cloud formation. Any rain is likely to be light and the clouds will have lesss vertical extent.