WINTER WEATHER FORECASTING THROUGHOUT THE EASTERN UNITED-STATES .3. THE EFFECTS OF TOPOGRAPHY AND THE VARIABILITY OF WINTER WEATHER IN THE CAROLINAS AND VIRGINIA

Winter weather in the Carolinas and Virginia is highly variable and in fluenced by the area's diverse topography and geography. The Gulf Stre am, the highest mountains in the Appalachians, the largest coastal lag oonal system in the United States, and the region's southern latitude combine to produce an array of weather events, particularly during the winter season, that pose substantial challenges to forecasters. The i nfluence of the region's topography upon the evolution of winter weath er systems, such as cold-air damming and frontogenesis, is discussed, Conceptual models and specific case studies are examined to illustrate the region's vast assortment of winter weather hazards including prol onged heavy sleet, heavy snow, strong convection, and coastal flooding . The weather associated with these topographic and meteorological fea tures is often difficult for operational dynamical models to resolve. Forecasting precipitation type within the region can be especially dif ficult. An objective technique to forecast wintry precipitation across North Carolina is presented to illustrate a locally developed forecas t tool used operationally to supplement the centrally produced numeric al guidance. The development of other forecast tools is being pursued through collaborative studies between the National Weather Service For ecast Office in Raleigh-Durham, North Carolina, and the Department of Marine, Earth and Atmospheric Sciences at North Carolina State Univers ity.