The boundary layer winds and downward vertical motion fields associated with a PSU/NCAR MM5 simulation of Supertyphoon Herb (1996) are examined. A spatial and temporal correlation is found to exist between the two parameters on the lee side of Taiwan's Central Mountain Range as the tropical cyclone traverses the island. Many questions arise from this occurrence. As orographically induced heavy precipitation is observed to fall on the windward slopes, it is hypothesized that the resulting extremely dry, low theta-e air mixes toward the surface. This downsloping air is seen to propagate as the environmental flow associated with the typhoon is oriented approximately parallel to the topography.