The relationship between primary convection over the mountains and secondary convection over the plains is examined along the Front Range of northeastern Colorado. Data collected from the Federal Aviation Administration Terminal Doppler Weather Radar indicate that thunderstorms over mountainous terrain typically produce plains thunderstorms by one of three mechanisms, or transition modes: initiation along convergent outflows, propagation along existing convergence lines, and propagation behind well-developed cold pools. Analysis of sounding data indicates which temperature and wind profiles favor each mode. The results of this study have the potential to be used operationally in short-term forecasting.
