Description
For each data point, the hydrostatically computed vertical velocity is compared to the theoretical fall rate. If the hydrostatic value is more than three times the theoretical value or the two values are of opposite sign, the point is discarded. If the hydrostatic value is greater than 1.35 times the theoretical value, the point is diagnosed as a fast fall.
If more than 50% of valid points (points not discarded during check) are diagnosed as fast fall, the sounding is labeled a fast fall.