Observations of Storm/environment Interactions

During VORTEX in 1998 and 1999 various types of pre-existing boundaries were the target of investigation. The data collected suggest a plethora of interesting hypotheses regarding boundary evolution and behavior leading to convective initiation. Embedded vortices have been observed in the Great Plains dryline and the Denver Convergence Vorticity Zone (DCVZ), on scales of tens of meters to several kilometers. These vortices may protect rising plumes of moist boundary layer air from entrainment of nearby drier air, thereby playing a role in formation of convective clouds along the boundary. Additionally, observations in the dryline and DCVZ include the moist/dry air transition zone collapsing down to several tens of meters, the various magnitudes of the horizontal shear across the boundaries, and the 3-dimensional vorticity structure. The observed character of boundaries could have important implications for supercell evolution and tornado production as it is now known that supercells are more likely to produce tornadoes after interacting with boundaries. Further, there are important implications for supercell initiation.