The most interesting thing to me in these images is what appears to be pretty significant attenuation. At S-band (~10-11 cm wavelength, which includes the bands at which the WSR88Ds operate), attenuation through meteorological media tends to be relatively minor, only becoming noticeable/appreciable with long path-lengths through heavy precipitation; for example, attenuation looking "down" a squall line can be very significant. However, considering the area "down-radial" of the high reflectivity area is very muted (with greater down-radial Zh for azimuths either side of that higher echo), it looks like a case of significant (anomalously significant) attenuation. The only thing that makes me a bit questionable about that, however, is the "crispness" (i.e. characterized by strong gradients) in the Zh field for radials counterclockwise to those that pass through the reflectivity maximum (shown in the zoomed-in image). Judging from sfc obs and the reflectivity image, it looks like the precip type at the surface was melting snow [for example, Thedford ob is light rain with T=35F at 10pm CST, and interpolating the evening soundings from OAX and LBF for the Thedford area would support some potential for melting snow (looking at LBF) or perhaps some sleet (modifying OAX a little)], so the Zh is high likely as a result of giant, water-coated melting snowflakes or wet sleet. That doesn't explain, however, why attenuation appears to have been so significant. It's slightly possible that there actually were two NW-SE "bands" with a natural break in the precip to the NW of this high-Zh echo, but I find that more unlikely than severe attenuation.
