Microphysical and quad-Doppler observations of the BAMEX 29 June 2003 MCS

On 29 June 2003, the NRL and NOAA P-3 sampled a mesoscale convective system (MCS) over north-central Kansas and far south-central Nebraska. The NOAA P-3 obtained measurements of particle size distributions from two dimensional cloud (2D-C) and precipitation (2D-P) probes during quasi-Lagrangian spiral descents through the melting layer behind the leading convective line. Both aircraft were equipped with dual-Doppler radars, enabling quad-Doppler retrieval of the wind field within the MCS.

A small squall-line developed rapidly on the south side of the MCS. Concurrent with this rapid development were observations of a sharp vertical gradient in radar reflectivity across the melting layer, in an area with low relative humidity. This rapid development was also concurrent with an intensification of the forward and downward flow of the rear inflow jet, as revealed from the quad-Doppler data. Microphysical data from the 2D-C and 2D-P probes during a spiral descent across the rear inflow jet revealed that ice was present down to 8 °C. Strong latent cooling may have resulted in negative buoyancy, thus enhancing the downward flow of the rear inflow jet. In this paper, the radar, kinematic, thermodynamic and microphysical structure and evolution of this MCS will be presented.