Synoptic features of orographically enhanced heavy rainfall on the east coast of Korea associated with Typhoon Rusa (2002)

A record‐breaking heavy rainfall event, with a 24‐hr accumulated rainfall of 870.5 mm, occurred in a coastal area at the foot of a mountain range in the central‐eastern part of the Korean Peninsula during the passage of Typhoon Rusa (2002). Synoptic features of this case were investigated via high‐resolution numerical analysis and forecast fields obtained from the PSU/NCAR MM5. The main causes of this localized heavy rainfall include: 1) strong low‐level convergence of moist air from the sea into the coastal/mountainous area; 2) consequent orographic lifting; 3) low levels of lifting condensation and free convection; and 4) release of potential instability by orographic lifting to trigger deep convection.