|Tornado||STP ≥ 1|
|Hail||MUCAPE ≥ 1000 J/kg, Eff. Shear ≥ 20 kt|
|Wind||MUCAPE ≥ 250 J/kg, Eff. Shear ≥ 20 kt|
Conceptually, PMM (probability-matched mean) is a variation of the ensemble mean with the original ensemble amplitude restored. At each grid point, the ensemble mean value is replaced with a value from the full distribution of individual member forecasts whose rank matches the point's rank within the ensemble mean distribution. See Ebert (2001, MWR) for more details.
LPMM (localized PMM) is a new technique from Clark (2017, WAF) wherein the PMM calculation is restricted to grid points inside some radius of influence, preventing precipitation in geographically distant areas from influencing the local value. On this site, we use r=110 km.