The Storm Prediction Center (SPC) and

Abstract

Objective forecast verification was conducted for the second year in near real-time during the 2013 Hazardous Weather Testbed (HWT) Spring Forecasting Experiment (2013 SFE). As part of the daily activities, experimental probabilistic forecasts for severe thunderstorms were created. These forecasts were then evaluated the next day via webpages with preliminary local storm reports (LSR) serving as the verification dataset. The idea was to further explore the value of incorporating verification metrics by comparing various scores to subjective evaluations from the participants. In addition to the forecast verification metrics examined in the 2012 SFE, the relative skill score was introduced since it was designed with a baseline reference capable of measuring skill of rare-event forecasts (i.e. severe thunderstorms). Results suggested that the relative skill scores were generally better on days with more severe weather reports. Further, the participants generated skillful forecasts at the lower probability thresholds, as the relative skill scores were predominately positive in accordance with favorable subjective ratings. ______________