In an era of significant federal government budget austerity for civil aviation operations, it has become essential to improve Air Traffic Control (ATC) productivity. This report summarizes the results of an exploratory field measurement program conducted during summer 2005 to assess ATC productivity benefits of the Corridor Integrated Weather System (CIWS). Real-time observations of CIWS product usage during multi-day thunderstorm events were carried out at eight U.S. Air Route Traffic Control Centers (ARTCC). The real time observations data were used in conjunction with specific in-depth case study analyses to assess the CIWS productivity enhancements associated with convective weather impact mitigation plan development and implementation. Comparisons of ARTCC operations between facilities with and without access to CIWS were alos made to further identify CIWS contributions to improved ATC productivity.