Extended Abstract (172K)1.5
A mesoscale analysis of the Lubbock area bow echo of 30 May 2001
Caleb J. Midgley, Texas Tech University, Lubbock, TX; and M. R. Conder, A. L. Doggett, and S. W. Weinbeck
The tendency for certain convective systems to develop a bow-shaped reflectivity signature is an ongoing subject of current research. More specifically, the need for observational data to verify modeling studies has become particularly important, as various modeling studies have shown significant correlation with storm-scale signatures that are observed in the field. The development of such systems through controlled simulations with a corresponding case study to use as a comparative backdrop seems to be a need, effectively bridging the observational/computational gap that appears in some of the literature. To do this, comprehensive bow echo datasets must be gathered for such studies. Specifically, datasets stratified by generalized pre-convective environments, such as northwest flow events, should be generated and then tested against control simulations. At this point, the authors know of several datasets that have been gathered and the following study seeks to contribute to the efforts of these researchers.
The bow echo event in question occurred on May 30, 2001 near Lubbock, TX. Several locations reported winds in excess of 40 m/s, with a larger swath roughly 200 km along its major axis reporting winds in excess of 26 m/s. Although this event does not meet the specific criteria for a derecho as described by Johns and Hirt (1987), the severity of surface winds within a weakly forced and marginally sheared environment raises questions as to what mechanism was responsible for such extreme wind speeds. Synoptic and mesoscale features on this day will be compared to numerical simulations run on the MM5 and RAMS model. The ability of mesoscale models to develop convection and subsequent storm-scale signatures will be analyzed. Should the models adequately simulate the bow-echo in question, vorticity budget analyses will be conducted to assess sources for mid-level vortex formation.
Session 1, Mesoscale Convective Systems I
Monday, 12 August 2002, 10:30 AM-12:00 PM
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