Thunderstorms above Frontal Surfaces in Environments without Positive CAPE. Part II: Organization and Instability Mechanisms

摘要: Abstract The second of two papers describing thunderstorms that occur above frontal surfaces, frequently in environments without positive convective available potential energy (CAPE), focuses on an impressive outbreak elevated during AVE-SESAME I. It is shown the occurred three impulses, each which developed warm sector before propagating onto surface; subsequent over surface. While sector, convection was supported by extremely unstable boundary layer. However, this quickly diminished surface and continued for many hours essentially stable hydrostatic environment. During lifetime these mesoscale updrafts moved with areas, maintaining nearly steady-state systems strong low-level inflow. environment found to be symmetrically neutral region in...