Validation of University of Wisconsin Convective Initiation (UWCI) algorithm

The University of Wisconsin Convective Initiation (UWCI) algorithm has been developed for use with GOES Imagers for nowcasting convective initiation. The UWCI algorithm utilizes only infrared measurements allowing for day/night independence (24 hour coverage). The UWCI algorithm computes GOES Imager infrared window channel box-averaged cloud top cooling rates and creates convective initiation nowcasts based upon a combination of cloud top cooling and satellite-derived cloud top type/phase trends. The UWCI algorithm is currently being run in real-time at the University of Wisconsin – Cooperative Institute for Meteorological Satellite Studies (UW-CIMSS) for operational convective decision support evaluation. The UWCI algorithm has been validated against first strike cloud-to-ground (CG) lightning strike for 23 convective afternoons during the Spring and Summer of 2008 and 2009 over the Central and Southern Plains of the United States. The mean probability of detection (POD) is 55.4% and mean false alarm ratio (FAR) is 26.0% for regions within a Storm Prediction Center severe storm slight risk or greater area and 46.4% POD, 35.0% FAR over the entire validation domain. Additional validation statistics are being compiled for nighttime hours and will also be included. This presentation will focus on the UWCI validation study, examine lead-time of UWCI nowcasts of first CG lightning strike, and breakdown synoptic conditions where the UWCI algorithm performs better and worse than the mean statistics.