Vertically integrated ice – a new lightning nowcasting tool

Previous studies have shown that mixed-phase microphysics are required for charge separation and subsequent lightning discharge. Due to its ability to scan the atmosphere at multiple altitudes, Doppler weather radar has the ability to detect the presence of mixed-phase regions within convective cells. This study analyzed data from the Weather Surveillance Radar – 1988 Doppler in Houston, Texas over 10 summers to determine the cloud-to-ground lightning nowcasting ability of a new radar-derived product called vertically integrated ice. The analysis resulted in Critical Success Index values as high as 0.64 and lead times for first cloud-to-ground flash up to 23 minutes. Real-time images of vertically integrated ice were incorporated into forecaster workstation displays at Weather Forecast Offices in Houston/Galveston and Fort Worth/Dallas. Preliminary forecaster feedback suggests that vertically integrated ice has the potential to aid in situational awareness of a cell's lightning potential and to be an effective decision support tool for airport weather warnings and severe thunderstorm warnings.