Investigation of the comma-head stability structure of wintertime mid-latitude cyclones using high-resolution observations

The Profiling of Winter Storms (PLOWS) field campaign sampled twenty-four winter cyclones over the course of the 2008-2009 and 2009-2010 winter seasons. The goal of this field campaign was to investigate the distribution of instability that leads to precipitation substructures found in the comma-head (wrap-around) region of wintertime cyclones. The wrap-around region is comprised of two sectors: northern and southern. The southern sector is characterized by dry air advancing northward over the warm front. This dry air intrusion produces potential instability that is released and forms convective precipitation structures that are often observed in this region. This study uses profiling radars and rawinsonde data to investigate the frontal and stability structure in the wrap-around region of the five winter cyclones that best sampled the interface between the dry slot air and the precipitation sector. Potential instability was found to be present in each of these cases despite being vastly different cyclones. The cyclones in this study had varying frontal structures, origins, strengths, and upper level forcing, but they all had potential instability present. Based on these analyses, the moist/dry interface on the south side of the wrap-around region of wintertime continental cyclones is characterized by deep convective cells that have heights reaching the tropopause in many cases. The impacts of this study will lead to an increased understanding of convective snowfall. The high-resolution view of winter storms that has been provided by the remote sensing instrumentation used during PLOWS can guide forecasters to correct their forecasts in the short-term and provide better nowcasting abilities