The United States National Weather Service has implemented the communication infrastructure that facili- tates the central collection and distribution of base level data in real time from 130 NEXRAD sites to users in govern- ment agencies, universities, and private industries. The Na- tional Severe Storms Laboratory is utilizing the infrastruc- ture to integrate the radars within a system to produce a 3D radar mosaic grid for contiguous United States. The mosaic system takes base level data from all available radars at any given time, performs quality control, and then combines re- flectivity observations from individual radars onto a single unified 3D Cartesian frame. The 3-D radar mosaic is cur- rently generated at 1-km horizontal resolution over 21 ver- tical levels and a 5-min update cycle. The 3D reflectivity grid can be used for multi-sensor severe storm algorithms, regional rainfall products generation, aviation weather appli- cations, and data assimilations for convective scale numer- ical weather modeling as well as serving as an operational- research test bed. Preliminary tests of the system have shown that the high-resolution rapid update national 3D reflectivity mosaic can be generated in real-time with less than 10 min latency using modest computer resources. ture, has instituted a National Mosaic and multi-sensor QPE (Quantitative Precipitation Estimation), or NMQ, system and research program. The NMQ system takes base level data from all available radars at any given time, performs qual- ity control, and then combines reflectivity observations from individual radars onto a unified 3D Cartesian grid that cov- ers the contiguous United States (CONUS). The CONUS 3D radar mosaic grid has a 1-km horizontal resolution over 21 vertical levels with a 5-minute update cycle.