VIL Density as a Hail Indicator

Abstract
In current severe thunderstorm warning operations, forecasters frequently use the vertically integrated liquid water content (VIL) product from the WSR-88D to estimate thunderstorm severity and, particularly, hail size. Since VIL varies greatly based on airmass characteristics, forecasters have typically determined a threshold VIL to be used for each new thunderstorm event. A product that is independent of airmass characteristics, and thus independent of season and geographic location, would be more desirable in an operational warning environment. It has been observed that high-topped thunderstorms with high VILs do not always produce large hail. It has also been observed that low-topped thunderstorms with low VILs occasionally do produce large hail. However, the maximum reflectivity in both high-topped and low-topped thunderstorms is similar when both produce similar-sized hail. From this, it was hypothesized that dividing the VIL by the echo top would “normalize” the VIL and produce a common va... Abstract In current severe thunderstorm warning operations, forecasters frequently use the vertically integrated liquid water content (VIL) product from the WSR-88D to estimate thunderstorm severity and, particularly, hail size. Since VIL varies greatly based on airmass characteristics, forecasters have typically determined a threshold VIL to be used for each new thunderstorm event. A product that is independent of airmass characteristics, and thus independent of season and geographic location, would be more desirable in an operational warning environment. It has been observed that high-topped thunderstorms with high VILs do not always produce large hail. It has also been observed that low-topped thunderstorms with low VILs occasionally do produce large hail. However, the maximum reflectivity in both high-topped and low-topped thunderstorms is similar when both produce similar-sized hail. From this, it was hypothesized that dividing the VIL by the echo top would “normalize” the VIL and produce a common va...

This publication has 0 references indexed in Scilit: