Rear-inflow structure in severe and non-severe bow-echo observed by airborne Doppler radar during BAMEX

The Bow-Echo and Mesoscale Convective Vortex Experiment (BAMEX) was an effort during the summer of 2003 to collect specialized observations, using highly mobile platforms, of bow-echo mesoscale convective systems (MCSs) in the midwest U.S. Analyses of several such events is presented to illustrate the complex precipitation and kinematic structure of these MCSs, particularly the rear-inflow jet structure and leading edge vorticity features. In spite of common horizontal radar structures (e.g., bowing of the leading convective line) and the presence of strong (i.e. > 30 m/s low-level rear inflow jets) not all strong bowing systems produced damaging surface winds. The MCSs examined include the non-severe 10 June event (IOP-7), the severe 6 July event (IOP18), and the severe 4 July event (IOP17). Basic data are from the airborne Doppler radar data collected by the NOAA P-3 and the NCAR ELDORA radar, mounted on the NRL P-3. Winds analyses from many passes are examined over a 4-hour period. On several of the passes a "quad-Doppler" analysis is performed to merge the ELDORA and NOAA P-3 data in a common synthesis. Horizontal and vertical cross sections of line relative flow and radar reflectivity are shown for the six analysis times to show the evolution of the line structure, book-end vortices and rear inflow jet. Dropsondes observations show a strong near-surface inversion that we speculate perhaps prevented downward penetration of the high momentum rear-inflow air to the surface in the non-severe event.