Ron W. Przybylinski

The Bow Echo and MCV Experiment: Observations and Opportunities

The Bow Echo and Mesoscale Convective Vortex Experiment (BAMEX) is a research investigation using highly mobile platforms to examine the life cycles of mesoscale convective systems. It represents a combination of two related investigations to study (a) bow echoes, principally those that produce damaging surface winds and last at least 4 h, and (b) larger convective systems that produce long-lived mesoscale convective vortices (MCVs). The field phase of BAMEX utilized three instrumented research aircraft and an array of mobile ground-based instruments. Two long-range turboprop aircraft were equipped with pseudo-dual-Doppler radar capability, the third aircraft was a jet equipped with dropsondes. The aircraft documented the environmental structure of mesoscale convective systems (MCSs), observed the kinematic and thermodynamic structure of the convective line and stratiform regions (where rear-inflow jets and MCVs reside), and captured the structure of mature MCVs. The ground-based instruments augmented sou...

Damaging surface wind mechanisms within the 10 June 2003 Saint Louis bow echo during bamex

Abstract Detailed radar and damage survey analyses of a severe bow echo event that occurred on 10 June 2003 during the Bow Echo and Mesoscale Convective Vortex (MCV) Experiment are presented. A bow echo formed just east of Saint Louis, Missouri, and produced a continuous straight-line wind damage swath approximately 8 km in width and 50 km in length along with five F0–F1 tornadoes. Careful superposition of the damage survey analysis and Weather Surveillance Radar-1988 Doppler (WSR-88D) data from Saint Charles, Missouri (KLSX), showed that the primary straight-line wind damage swath was not collocated with the bow echo apex as has been suggested in previous studies. Rather, the primary damage swath was found north of the bow apex, collocated with a low-level vortex that formed on the leading edge of the bow echo. Much of the primary damage swath appeared to have been created by the low-level vortex. Moreover, most of the surface straight-line wind damage was generated during the early stages of bow echo mo...

Vortex Structure and Evolution within Bow Echoes. Part I: Single-Doppler and Damage Analysis of the 29 June 1998 Derecho

Abstract Single-Doppler radar along with damage observations are examined to investigate the structural evolution of vortices observed within the 29 June 1998 derecho event that propagated through southeastern Iowa into central and eastern Illinois. A total of 13 meso-γ-scale vortices observed primarily at low levels (0–3 km AGL) along the leading edge of the convective system were detected by the Weather Surveillance Radar-1988 Doppler (WSR-88D) radars at Davenport, Iowa, and Lincoln, Illinois. All but one of the vortices formed after the system evolved into a bow echo. Ten of the vortices formed north of the apex while three formed south of the apex. Seven of the vortices produced tornadoes that created F0–F1 surface damage. None of the vortices exhibited appreciable upscale growth. Careful analysis of the radar data suggests that it may be possible to discern between the tornadic and nontornadic vortices. The tornadic vortices tended to be stronger, longer-lived, and deeper than their nontornadic count...

Storm Reflectivity and Mesocyclone Evolution Associated with the 15 April 1994 Squall Line over Kentucky and Southern Indiana

Abstract A long-lived highly organized squall line moved rapidly across the middle Mississippi and Ohio Valleys on 15 April 1994 within a moderately unstable, strongly sheared environment. Over Kentucky and southern Indiana, the line contained several bowing segments (bow echoes) that resulted in widespread wind damage, numerous shear vortices/rotational circulations, and several tornadoes that produced F0–F2 damage. In this study, the Louisville–Fort Knox WSR-88D is used to present a thorough discussion of a particularly long-tracked bowing line segment over central Kentucky that exhibited a very complex and detailed evolution, more so than any other segment throughout the life span of the squall line. Specifically, this segment produced abundant straight-line wind damage; cyclic, multiple core cyclonic circulations, some of which met mesocyclone criteria; several tornadoes; and embedded high precipitation supercell-like structure that evolved into a rotating comma head–comma tail pattern. The bowing seg...