The Dissipation of a Left-Moving Cell in a Severe Storm Environment

Abstract

Abstract Observations have shown that thunderstorms sometimes undergo updraft splitting, where one updraft moves to the right of the mean tropospheric wind and the other to the left. Observations also show that the left-moving updraft tends to dissipate approximately 15 min after the splitting process. The right-moving cell, however, may exist for up to a few hours. Idealized modeling studies suggest that this behavior is related to the clockwise turning of the environmental shear vectors with height. The interaction between the environmental shear and the storms updraft produces a high–low pressure couplet oriented downshear. This pressure pattern produces favorable vertical accelerations for the right mover. This same process inhibits upward motion for the left mover. In this paper an idealized simulation is presented that suggests an additional process that contributed to the decay of the left-moving updraft. Analysis of low-level storm-relative winds for the left-moving cell indicated that the inflow ...