Satellite evidence of Rear Flank Downdrafts (RFD)?
Small areas of 6.7µm darkening have often been observed just upstream of mature strong/severe storms in highly sheared environments. To date, there are no formal studies linking these darkbands to the development of Rear Flank Downdrafts.
However, consider the image displayed below. The flow through these watervapor darkbands most likely conserves its potential temperature and moisture. Therefore the darkening must be a result of subsidence in a layer. Whether this darkening can produce enough of a vertical displacement to initiate or assist the development of a RFD is not known. However, the mechanisms that lead to the development of an RFD is still open to question.
