Effects of Appalachian topography on precipitation from landfalling hurricanes

A thorough analysis of rainfall distributions associated with tropical cyclones that have impinged upon or impacted the southern and central Appalachian mountain range is conducted using the North America Regional Reanalysis (NARR) and the European Center for Medium-Range Weather Forecasts (ECMWF). Based on the relative positions between the tropical cyclone tracks and the orientation of the Appalachian mountains, four storm tracks and their associated rainfall patterns are classified. Local rainfall maxima are obtained identifying areas with the highest potential for flooding for each representative track. For storm tracks running parallel on the eastern side of the Appalachians (Category B), the heavy rainfall is located along eastern slopes with the heaviest precipitation falling on western North Carolina and central Virginia. Storm tracks that run parallel on the western side of the Appalachians (Category C) show the heaviest precipitation falling on the eastern slopes of western North Carolina. For storm tracks running approximately perpendicular to the mountain range (Categories A and D), maximum rainfall is located along the base and mountains of central Virginia.

These locations are analyzed and conceptualized using category composites and individual case studies. The objective of this study is to improve the skill and precision of future forecasts by identifying specific areas of enhanced precipitation associated with landfalling tropical cyclones.