A Study of a Dryline Convective Downburst

Abstract

During the afternoon of 15 June 2005, convective storms developed along and west of the dryline over eastern Colorado and New Mexico. One such storm tracked eastward into Cimarron County, Oklahoma and produced a strong downburst at Kenton. The dryline, as it tracked eastward over the western Oklahoma Panhandle, established favorable conditions for hybrid microbursts by enhancing vertical circulation west of the dryline and hence, the depth of the convective boundary layer (CBL). Prior to convective initiation, the Geostationary Operational Environmental Satellite (GOES) Hybrid Microburst Index (HMI) and Wet Microburst Severity Index (WMSI) products indicated elevated values over the western Oklahoma Panhandle. In addition, lightning data imagery, from the National Lightning Detection Network (NLDN), was compared to radar and satellite imagery and surface observations of downburst winds. It was observed that suppressed cloud-to-ground (CG) lightning flash rates accompanied downburst occurrence with this storm. This paper will examine the environmental factors that resulted in downburst generation and associated storm electrification. Use of the Geostationary Operational Environmental Satellite (GOES) Wet Microburst Severity Index (WMSI) and Hybrid Microburst Index (HMI) products will be highlighted to demonstrate effectiveness in the assessment of downburst potential. Radar reflectivity and NLDN imagery will be presented to describe convective morphology and electrical behavior with this dryline convective storm event.