CORRESPONDENCE Comments on ‘‘Preconditioning Deep Convection with Cumulus Congestus’’

The hypothesis that cumulus congestus clouds in the tropics moisten dry layers above the boundary layer and promote the formation of deep moist convection was tested by Hohenegger and Stevens. This comment asks whether their hypothesis is also true for cumulus congestus clouds and deep moist convection in the midlatitudes. This comment also requests clarification on how their expression for moisture convergence is calculated and used in their article, especially in light of previous studies showing that moisture flux con-vergence is a less-than-adequate diagnostic for convection initiation and that deep moist convection requires sufficient lift and instability, in addition to sufficient moisture. Hohenegger and Stevens (2013) present compelling multiple arguments that indicate that the time scale is much too slow for congestus to precondition or moisten the atmosphere for deep moist convection, that environ-ments with prolonged occurrence of congestus clouds are not more likely to grow into deep moist convection, and that the presence of congestus does not lead to greate