Polarimetric radar and electrical structure of a multicell storm

We present data from the late stages of a multicellular storm occurring on 28-29 June 2004 during the Thunderstorm Electrification and Lightning Experiment (TELEX) field program in central Oklahoma. Three-dimensional (3-D) vector electric field (measured by balloon sounding), total lighting mapping, and polarimetric radar are utilized.

Above the melting level, enhanced Z_dr and K_dp, and a drop in ρ_hv at the cellular / updraft scale preceded the initial lightning flash in the storm. The first six flashes were negative cloud to ground flashes. The polarimetric signature in question is associated with lofted raindrops which serve as nuclei for riming graupel upon glaciation (Bringi et al. 1997, Jameson et al. 1996). The signature was absent in nearby cells, which did not produce lightning. The polarimetric data are discussed in the context of charge geometry within the storm as inferred from each flash within the storm and from vector electric field data.