Quantifying the Latency within Mosaicked Radar Products and Assessing Impacts on Operations

 Herein, the pixel latency within the Multi-Radar/Multi-Sensor (MRMS) system and its effects on nowcasting is investigated. To do this, a new product, referred to as a “time-stamp” mosaic is created. It is generated by assigning to each pixel the age of the radar returns that were provided to it. In winter, when many radars are run in VCPs 31 and 32, the mean latency is higher. Likewise, the latency decreases in spring and summer. The effects of latency on meaningful interpretation of the weather is further investigated by comparing the pixel latency to average time rates of change in reflectivity. As is expectable, more rapidly evolving systems have higher errors. Conversely, in winter, the errors are lower because precipitation systems usually evolve more slowly during the cold season. There are also differences between the average pixel latency in the western versus the eastern United States that lead to differing amounts of error. This information can be used to assign uncertainty estimates on the mosaicked reflectivity. A demonstration of this type of tool and how it might be beneficially used is provided.