High-resolution surface and tower observations of the southern Plains dryline during Project SONDE—2005

Drylines have long been identified as locations favorable for the development of deep moist convection. The processes responsible for the development and propagation of the dryline are becoming better understood, but the impact of each control varies from case to case. For example, previous studies have identified the vertical transport of horizontal momentum to the west of the dryline, affecting directly the boundary layer convergence present in the dryline convergence zone (DCZ). One of the goals of this research is to relate the variability of this vertical momentum transport to the observed differences in dryline position and structure, and convective initiation.

The Simultaneous Observations of the Near-Dryline Environment (SONDE-2005) project intensely observed multiple drylines in the southern Plains during the spring of 2005. A large array of surface-based instrumentation was used, including four mobile mesonets, a 200 m tower, a vertical wind profiler, the UMass 95 GHz radar, the 45 stations of the West Texas Mesonet, and three SBCCOM towers (10 m AGL) sampling at 10 Hz.

Selected observations of forward and retreating dryline passages will be presented and related to previous findings. Preliminary conclusions regarding vertical momentum transport, along-dryline variability, DCZ structure, and retrogression will be offered.