Extended Abstract (512K)13.3
Tornadogenesis within quasi-linear convective systems. Part I: Radar and storm damage analysis of the 29 June 1998 derecho
Justin M. Arnott, Lyndon State College, Lyndonville, VT; and N. T. Atkins
On 29 June 1998, a line of supercells initiated along a stationary front in central Iowa, transitioned into a bow echo, and subsequently moved southeastward. This bow echo spawned at least eight tornadoes and produced widespread straight-line wind damage. Evolution of the bow echo is presented using radar data in addition to wind damage and tornado reports obtained from Storm Data. Eleven low-level, radar-detected vortices are also documented. Superposition of tornado reports onto these vortices indicates that 45% of the vortices were tornadic. A detailed examination of these vortices reveals that they are short-lived, low-level, and exhibit an average diameter of 4.7km. While wind damage reports were located indiscriminately with respect to the bow echo, this study found that both tornadic and non-tornadic vortices formed in a preferred region north of the bow echo apex, consistent with previous studies. Forecasting implications of these results will also be discussed.
Session 13, Tornadic Storms
Thursday, 15 August 2002, 10:30 AM-12:00 PM
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