Abstract: In this paper, several possible mechanisms of the genesis of medium scale disturbances are approached with a multilevel linear model, among them are baroclinic shear, static stability, and condensation heating. The structure of medium-scale disturbances is also discussed. Finally, combining theoretical results obtained in this and other work with some synoptic facts, weppropose some interesting conclusions. This work could be useful for researching medium scale disturbances in depth.