Anvil Level/9-11-km SR Winds (kts)

The Anvil Level SR (Storm Relative) winds and SR winds from 9-11-km are meant to discriminate supercell type. In general, upper-level SR winds less than 40 knots correspond to "high precipitation" supercells, 40-60 knots SR winds denote "classic" supercells, while SR winds greater than 60 knots correspond to "low precipitation" supercells.

Reference:
Rasmussen, E. N., and J. M. Straka, 1998: Variations in supercell morphology. Part I: Observations of the role of upper-level storm-relative flow. Mon. Wea. Rev., 126, 2406-2421.