May 21 - July 30
Verification of Earth Network's Dangerous Thunderstorm Alerts and National Weather Service Warnings
Rebecca DiLuzio, Tiffany Meyer, Kristin Calhoun, and Matthew Elliott
What is already known:
- Increases in total lightning activity have been known to precede severe weather events.
- Earth Networks Inc. releases Dangerous Thunderstorm Alerts (DTAs) when their Total Lightning Network reads lightning flash rates that breach a certain threshold.
- DTAs may be a new aid in operational forecasting of severe weather but must be verified first.
What this study adds:
- When DTAs Probability of Detection (POD) was highest, so was their False Alarm Ratio (FAR).
- DTAs performed best during the months with the most convective activity.
- DTAs performed similar to NWS tornado warnings over the course of a year, but performed poorly when compared to NWS severe thunderstorm warnings.
Abstract:
Earth Networks Incorporated (ENI) has expressed the potential for their Dangerous Thunderstorm Alerts (DTAs) to increase lead time by an additional nine minutes over current National Weather Service (NWS) tornado warnings while maintaining a similar probability of detection (POD) and false alarm ratio (FAR). These automated, storm-based alerts combine lightning-based storm tracking with total lightning flash rate thresholds to designate regions with an increased potential for severe and hazardous weather. ENI produces alert polygons at three different levels: (1) basic thunderstorm, (2) significant thunderstorm, and (3) dangerous thunderstorm. Verification statistics (POD, FAR and lead time) were calculated for ENI’s level 3 DTAs and NWS severe thunderstorm and tornado warnings are calculated for a year of data, March 2013 through Feb 2014. A more in depth case study was done for 20 May 2013. The goal of this comparison is to evaluate how well DTAs perform relative to NWS warnings and if use within operational meteorology will improve warnings.