Development, Evolution, and Forcing of the Rear Inflow Jet Within the 29 June 2003 Kansas BAMEX Bow Echo

In the summer of 2003, the University of Illinois took part in the Bow Echo and MCV EXperiment (BAMEX), which was conducted over the central United States. BAMEX provided the best observations to date of mesoscale convective systems (MCSs). Our primary observation platforms were the NOAA P-3 and NRL P-3 aircraft, which were tasked to fly behind and ahead of developing and mature mesoscale convective systems (MCSs) and collect quad-Doppler radar and in-situ microphysical data. The talk will focus on observations made on June 29, 2003, when the complete evolution of a short lived bow echo was documented with both quad Doppler observations and a microphysical spiral directly behind the developing bow echo.

One common feature of MCSs is the presence of a rear inflow jet (RIJ), which plays a crucial role in supplying cool, dry midlevel air to aid in the production of the convective- and system-scale downdrafts. This study will use airborne quad-Doppler radar data to examine the complete life cycle of a squall-line MCS. The derived wind field and retrieved pressure patterns have been used to document the evolution of the RIJ, as well as its role in the evolution of the system. This study also utilizes observed cloud and precipitation particle size distributions, obtained while the aircraft descended in tight spirals through the depth of the RIJ at approximately the same fall rate as the observed precipitation particles. The size distributions obtained from 29 June are unique in that they are the only known particle observations obtained within the RIJ during the formative stage of a bow echo. This talk will focus on the forcing for the RIJ and its descent during the development of the bow echo.