Abstract : This report presents our findings from a three-year Rapid Transition Project (RTP) designed to develop and test a new environmental assessment concept in coordination with the Naval Pacific Meteorology and Oceanography Detachment, Fallon, NV, in support of the Naval Strike and Air Warfare Center (NSAWC). This project leverages the current operational on-demand atmospheric mesoscale modeling system to provide the core component for an extended capability called "Nowcast" that extracts and fuses the available multi-source sensor data and then shares the resulting common representation of the relevant environmental information as web-enabled products using standards-based, net-centric techniques appropriate for future military networks and operations. The groundwork for development of the Navy Nowcast capability began in 1998 when a forward-deployed mesoscale data analysis and forecast system, using a forerunner of the Coupled Ocean/Atmosphere Mesoscale Prediction-On Scene (COAMPS-OS-tm) system, was established at the Naval Meteorology and Oceanography (METOC) Centers worldwide. A year later, after informal consultation with end users, the Nowcast architecture, design elements, and communication requirements were documented (see Appendix), and development of a prototype system was begun. In 2002, an operational prototype was implemented at the Naval Pacific Meteorology and Oceanography Center-San Diego (NPMOC-SD), in support of the Joint Task Force Commander during Fleet Battle Experiment Juliet (FBEJ), a component of the larger U.S. Joint Forces Command Millennium Challenge 02 (MC02) experiment, in which live and simulated exercises were used to evaluate technological innovations. Positive reports from users indicated that Nowcast products provided remote users with unprecedented access to radar reflectivity (thunderstorm), cloud cover, and high-resolution surface wind products,high-resolution Nowcast and COAMPS-OS product