RHI cross section of through a microburst produced by virga from a low reflectivity storm at 2314:23 UTC 30 April 1995. The black box on (a) is enlarged in (b). Radar reflectivity and Doppler velocity are shown on the top and bottom figure in (a) and (b), respectively. The parent cell, outlined by the 25 dBZ contour, which produced the microburst is shown by the black arrow in (a). The fine line associated with the leading edge of the microburst is shown by the white arrow in the reflectivity scan in (b). The center of rotation accompanying an intense rotor at the leading edge of the microburst outflow is shown by the white arrow in the velocity scan in (b). Range rings and azimuths are every 5 km and 30 degrees in (a) and 2 km and 30 degrees in the velocity scan in (b),respectively. Schematic diagram of the flow patterns and the horizontal rotor is shown in the middle of (b). The gray shading in the schematic represents reflectivities greater than 0 DBZ.

Rotor circulations are horizontal vortex circulations that can result in severe turbulence. The velocity plot in figure b reveals that the aircraft penetrated an intense horizontal rotor. This is why the aircraft was struck by strong downward motions of ~10 m/s at ~2314 UTC.