We continue our exploration of alternative methods for assessing the goodness of NWS severe thunderstorm and tornado warnings. At a previous conference, we reported on our work to verify warnings geospatially on a high-resolution grid using data collected during a springtime warning experiment at the NOAA Hazardous Weather Testbed (HWT). For each grid point, we compute location-specific probability of detection, false alarm ratio, and various other skill statistics (e.g., critical success index), as well as lead time, departure time, and valid warning time for each event affecting the grid location. For the period and spatial domain of an entire storm event, we compute the averages of the above measures, as well as aggregate false alarm areas and times.
We will compare the effects of improved warning precision (area and duration) on the current and experimental verification schemes. In addition, we will explore the advantages, from a service improvement standpoint, of two potential upgrades to severe weather warning information that were tested in the HWT: 1) Threats-In-Motion where warning polygons move continuously with the storm threats, and 2) probabilistic information for locations where the threat levels are currently below warning criteria or for locations still downstream of current warnings.