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.