Using RUC-2 analysis parameters to identify severe convective wind environments

Severe weather parameters from Rapid Update Cycle (RUC) model analyses (at three hourly intervals) from 2003 are compared to 6355 reports of large hail, 7055 reports of damaging winds, 958 reports of tornadoes, and 377081 occurrences of lightning. It is shown that wind velocity, storm relative helicity, and wind shear fields discriminate the best between severe weather and ordinary convection. Additionally, it is shown that steep lapse rates and dry mid level air (traditional damaging wind parameters) generally do not discriminate between ordinary convection and convection that produces damaging winds, while the heights of the melting level and the level of free convection do. Parameters that discriminated between the severe and ordinary convection were combined into an algorithm to forecast damaging convective winds. The utility of the wind algorithm is demonstrated with a selection of cases that highlight common severe wind ingredients and failure modes.