Prognostic techniques for storm motion are crucial to Lagrangian-framework (storm-relative) evaluations of parameters such as helicity and wind velocity, which can be used to assess the potential for supercell formation, morphology, and for the risk of supercellular tornadoes. Several storm motion prediction methods have attained widespread operational and research use, the most common being one of several Maddox (1976) variations which applies a 30^o rightward and 75 percent of mean wind assumption, and more recently the Bunkers et al. (2000) algorithm. This examination verifies the performance of those two techniques using RUC-2 model initial proximity soundings (Thompson and Edwards 2002, this volume) for a nationwide database of 458 supercells bearing radar-derived storm motions. Statistical comparisons of observed supercell motions to algorithm-based storm motions are made for the full storm set, as well as for tornadic, nontornadic and significant tornadic (F2 or greater damage) subsets, in order to evaluate the utility of these two storm motion prediction methods.