Performance of the CASA radar network during the May 13, 2009 Anadarko tornado

On May 13, 2009, an EF2 tornado and 100 mph sustained straight-line winds devastated the towns of Gracemont and Anadarko, Oklahoma. The CASA 4-node radar network, a prototype for a new weather sensing paradigm, captured this event. CASA has deployed a network of X-band radars spaced 25 kilometers apart, enabling lower troposphere, high-resolution observations, and overlapping radar coverage. The radar system configures and executes coordinated surveillance and volumetric sector scans each minute to deliver optimal information for user decision-making. CASA's research encompasses the entire warning system from radar observation to the use of weather data by NWS forecasters, emergency managers, and the public. Our hypothesis is that CASA's high resolution, lower troposphere, multi-Doppler, geographically specific data will improve warning and response. The May 13 event demonstrates this end-to-end approach and how we are integrating physical, social and technical sciences and practitioner expertise to design and operate the network. For NWS forecasters, CASA's real-time assimilated wind products enhanced situation awareness of tornadic development, resulting in issuance of a tornado warning (in a real-time, non-operational warning experiment) with an additional 3 minutes of lead time, while the high resolution data provided better views of the hook echo and rotation couplet signatures. CASA's geographically specific data would enable emergency managers (in a post event analysis) to deploy spotters more effectively and map the tornado and damaging winds to specific neighborhoods in the town of Anadarko for public notification and first responder deployment. Finally, the May 13 event will be used to illustrate future areas for research and the potential for broader deployments of a CASA network.