Extreme rainfall and flooding from orographic thunderstorms in the central Appalachians

摘要: [1] The central Appalachian region has experienced some of the largest rainfall accumulations in world at time intervals less than 6 h, including 18 July 1942 Smethport, Pennsylvania, storm that produced 780 mm 5 h. The envelope curve flood peaks “small” drainage areas (less 1000 km2) is dominated by orographic thunderstorm systems, like Smethport storm. Orographic systems have catastrophic flooding Appalachians are examined through observational and numerical model analyses using Weather Research Forecasting (WRF) model. Analyses suggest frequency varies over small-scale variation may be linked to role complex terrain altering dynamics. Catastrophic along western margin four storms occurred on 18–19 (1889, 1942, 1977, 1996), which were associated with warm season extratropical characterized rapidly moving elements terrain. Along eastern interior Appalachians, “terrain-locked” convective 17–18 June 1949, August 1969, 27 1995, 11 2003. WRF simulations Little River (June 1949), Rapidan 1995), (18 1942) Redbank (18–19 1996) used characterize “ingredients” rainstorms Appalachians.