The Appalachian Mountains in the Eastern United States have a considerable impact on the day-to-day weather across the region. Significant weather events such as severe convection present a substantial challenge to forecast accurately when in the presence of complex terrain. This has been underscored by several high-impact supercell events in the Appalachian region, including those with significant tornadoes occurring at high elevations that caused damage and injuries. While there have been several studies that have explored terrain-induced effects on supercellular tornadoes and tornadogenesis, outside of individual case studies, few have more broadly examined the storm-scale modifications to a supercell thunderstorm as it interacts with topography. Additionally, the typical environments that produce severe wind, hail, or tornadoes across the elevated region has yet to be documented.
The project entails three integrated components. First, numerous severe and non-severe supercell cases within the central and southern Appalachians will be categorized according to a variety of climatological, environmental, and radar-based characteristics. Second, the project will evaluate how the inflow environment varies as each supercell traverses through the mountains, and whether those changes can predict supercell behavior (e.g., production of severe weather, storm lifetime, etc.). Third, idealized simulations initialized with composite soundings from subsets of observed cases will be performed to engender the development of a generalized conceptual model for use in operations and to clarify the governing physics of how terrain can modify supercell structure and produce severe weather.
This line of research is a collaborative effort with Dr. Casey Davenport (UNC Charlotte, six NWS forecast offices [Blacksburg (VA), Charleston (WV), Greenville-Spartanburg (SC), Jackson (KY), Morristown (TN), and Atlanta (GA)] and the Storm Prediction Center. The project is funded by a grant through the NOAA CSTAR Program.
Relevant Publications and Presentations:
McKeown, K. E., C. E. Davenport, S. M. Purpura, and M. D. Eastin, 2020: Radar characteristics of observed supercell thunderstorms interacting with the Appalachian Mountains. AGU Fall Meeting
Purpura, S. M., C. E. Davenport, K. E. McKeown, and M. D. Eastin, 2020: Environmental evolution of supercells interacting with the Appalachian Mountains. AGU Fall Meeting