WDRAFT Using Reflectivity
Vertically Integrated Liquid Water (VIL)
Simply add up the water equivalent of Z above each point add up water equivalent of Z (units of kgm-2). The VIL Technique developed for storm severity by Greene and Clark 1972. It is used to assess hail potential and also in the calculation of WDraft. Benchmark values of VIL are > 38 kgm-2 as a severe/non-severe threshold with values in excess of 43 kgm giving a high probability of severe weather. (Amburn and Wolf, 1997)
References: Weather and Forecasting: Amburn and Wolf 1997 Vol 12 pg 473-478
VIL Density
VIL Density (VIL normalized by Echo Top) may hold more promise. VIL density > 3.5 gm-3 is a good threshold for delineating severe hail from non-severe hail. If > 4 gm-3 severe hail has a high likelihood.
References: Weather and Forecasting: Edwards and Thompson 1998 Vol 13 pg 277-285
References: Weather and Forecasting: Edwards and Thompson 1998 Vol 13 pg 277-285
WDRAFT
WDRAFT is based on a statistical approach that correlates VIL density with observed reported wind gust at the surface in wet microburst situations. It has proven quite reliable over the years in Ontario and seems to pick up high winds with squall lines too.
Example output from WDRAFT