20 Years of R2O Interactions between NSSL and SPC including the Origin and Evolution of the NOAA Hazardous Weather Testbed

The NWS/Storm Prediction Center (SPC) completed its move from Kansas City, MO to Norman, OK in January, 1997.  The SPC relocated into the OAR/National Severe Storms Laboratory (NSSL) facility with a stated goal of reuniting the national severe storm forecasting and research components within NOAA.  This move was envisioned to enhance research-to-operations collaborations ultimately leading to improved operational NWS severe weather products and services.  A summary of the interactions is presented, including early collaborative efforts that helped identify and better understand cultural similarities and differences between round-the-clock operational forecasters and research scientists.  The importance of physical proximity, shared interests and common visions, and complementary skill sets that enabled the first Spring Program to occur in 2000 are discussed.  The development and growth of the early Spring Program through the gradual incorporation of broader community participation and a focus on cutting-edge numerical weather prediction model applications to severe weather forecasting is chronicled, highlighting the evolution of the NOAA Hazardous Weather Testbed into a preeminent center for successful R2O/O2R testbed activities.