Vertically Pointing Airborne Doppler Radar Observations of Kelvin Helmholtz Billows

A train of Kelvin Helmholtz billows in a deep stratiform cloud over a mountain range is documented using data from a high-resolution vertically pointing airborne Doppler radar. The billows had a spacing of 2-2.5 km and a small aspect ratio. The formation and decay of the billows appear to be related to flow acceleration over a mountain.