Radar reflectivity "blobs" observed by the Doppler on Wheels

It has been widely believed that the hook echo signature on radar develops as hydrometeors are advected around the rotating updraft on a supercell's right-rear flank. However, recent research using WSR-88D radar data suggests that some hook echoes form as a region of high radar reflectivity (termed reflectivity “blobs” by some investigators) descends toward the surface from the echo overhang on the right-rear flank of a supercell.

In this paper, we will document similar reflectivity features that have been observed in higher resolution Doppler on Wheels (DOW) radar data. Although the DOWs generally do not obtain data within the upper reaches of a storm as a WSR-88D would, the DOWs obtain significantly higher resolution data, both in space and time, at low altitudes within a storm. The DOW observations of reflectivity blobs might be of interest owing to questions about whether prior WSR-88D observations of blobs and their subsequent evolution into hook echoes were an artifact of the more limited resolution of the WSR-88D.