Space-time scale gaps continue to exist between numerical weather prediction (NWP) forecasts and distributed hydrologic models. This study investigates the open research problem of scaling organized thunderstorms and convection in mountainous terrain from NWP model scales down to the 1 ~ 4 km scales needed for hydrologic models. Focus is placed on the Appalachian region and the Front Range of the Rocky Mountains. Case studies which are characteristic of organized thunderstorms that produce heavy convective rainfall and catastrophic flooding in mountainous regions have been studied to explore the multi-scaling behavior of orographic precipitation. Differences in the topographic and meteorological dependencies and scales of spatial organization between western and eastern United States orographic thunderstorms have been specifically investigated. Multi-scale statistical properties of convective precipitation in the various case studies are linked to both topographic and meteorological influences.

The following questions will be addressed: (1) does spatial and space-time scaling exist as a common feature in convective orographic precipitation?, and (2) how do meteorological forcings and geographic location impact trends in orographic influences on the multi-scale statistical properties of heavy convective precipitation? Several case studies of non-orographic convective precipitation events will also be included to provide insight on the linkages between multi-scale behavior and meteorological differences between storms without the presence of orographic influences. The potential for developing a statistical downscaling model for orographic convective precipitation based on the interplay between meteorological forcings and topographic influences on the multi-scale properties of precipitation will be assessed.