Since no major rivers flow into the State of North Carolina, precipitation falling within the state is the primary natural source of water to replenish that region's rivers, soils, and groundwater reservoirs. As climate and population pressures change, water management and sustainability policies in North Carolina will be increasingly dependent on an improved understanding of precipitation variability in that region.

The premise of this NSF-funded study is that a novel climatology of precipitation system mode of delivery in North Carolina, developed with newly available high resolution precipitation and three-dimensional radar reflectivity data sets, will lead to improved regional climate and hydrological forecasts. Mode of delivery refers to the spatial, temporal and water phase characteristics of a precipitation system. Examples of mode of delivery that occur in North Carolina within various synoptic regimes include short duration and spatially heterogeneous convective cells, large mesoscale convective systems, widespread long-lasting frontal precipitation, tropical cyclones, and winter precipitation. Each mode of delivery may produce similar time-averaged precipitation totals, but have very different climate and hydrological impacts. A mode of delivery climatology will provide a unique tool for process-based downscaling of climate simulations.

This paper reports on the preliminary steps and early results in constructing the mode of delivery climatology. We present highlights of several case studies of different types of precipitation system morphology in North Carolina, in order to illustrate the methodology that will be used to build a multi-year climatology. The project is collaborating with the NOAA Satellite and Information Service at NCDC and the Renaissance Computing Institute at the University of North Carolina, Chapel Hill, to harness a multi-sensor precipitation dataset based on the portion of the NMQ Q2 national radar reflectivity mosaic centered on North Carolina to identify and analyze each precipitation system. The NCEP North American Regional Reanalysis products are used to characterize the large-scale environment of the cases.