Variations in the distributions of parameters that lead to deep moist convection from the National Center for Environmental Prediction (NCEP) and National Center for Atmospheric Research (NCAR) 42 year global reanalysis dataset have been analyzed for 3 domains. Although the variability of the distribution of convective parameters is a little higher in the Eastern United States, the Central United States adequately represents the distribution of both domains, and therefore serves as a comparison to the South American domain. CAPE has been roughly increasing in the Central United States since the late 1960's while South America has been exhibiting a downward trend in CAPE over the period. In fact, from 1970 to 1999 the two regions have exhibited very different characteristics when it comes to the distribution of CAPE.Deep shear in the presence of CAPE has not changed throughout the reanalysis period. Therefore, the increase of the product of CAPE and deep shear can be contributed to the increase of CAPE in the Central and Eastern United States.