A link acts down-scale when a dissipating MCS leaves in its wake an MCV that initiates a fresh outbreak of cumulonimbi. Whether or not an MCS produces an MCV, and whether or not an MCV initiates a fresh outbreak of cumulonimbi, depends partially on the local vertical wind shear.
Shear is both conducive and destructive to MCVs and subsequent moist convection.
It is conducive to MCVs in that tilting can produce vertical vorticity from vertically sheared winds' horizontal vorticity. Shear is destructive in that it can disrupt the coherence of the atmosphere's balanced vortical response to an MCS's latent heating, which shortens the life of an existing MCV or prevents one from forming at all. Even if an MCV does form, one that is short-lived is less likely to produce much isentropic ascent. Understanding the role of shear in the narrow range that favors MCVs and subsequent cumulonimbi, and better defining that range, may lead to improved forecasting of some of the MCSs that deliver flooding deluges and damaging winds. The author will examine the vertical wind shear in and around an MCS and its MCV in the Great Plains on 1-2 August 1996.