ANC’s nowcasts of convective likelihood will become available to forecasters in September, 2016. Therefore, it is important to evaluate these nowcasts quantitatively in order to provide statistical scores so that forecasters can have confidence using this product. However, evaluating gridded nowcasts of thunderstorm initiation is challenging because it is hard to delineate convective initiation objectively and distinguish it from existing storms. In addition, it is difficult to evaluate gridded nowcasts statistically because of the high sensitivity of statistical scores to small errors in location and/or timing, in part because areas with active convection are lumped together with areas with no convection. For this study, an objective method was used to classify radar observations as being new, ongoing, or decaying storms. To reduce the high sensitivity of statistical scores to small errors in location, a relaxation technique was applied to both the forecast and the truth fields. This paper presents the results of ANC’s performance using data within the May, 2012 to September, 2012 time frame.
Supplementary URL: http://www.mdl.nws.noaa.gov/ancView/conus/