MRMS Quality Control for Light Winter Precipitation

It is important for radar quality control (QC) algorithms to correctly remove nonmeteorological echo while retaining meteorological echo. Failure on either of these objectives presents users with an unrealistic display of ongoing precipitation, creating a challenge for those making weather-related decisions. The current Multi-Radar Multi-Sensor (MRMS) QC algorithm struggles to retain light precipitation echo (e.g., light rain, light snow, and drizzle), leading to such a challenge. The current algorithm was modified to improve retention of light precipitation echo.

To evaluate how the new algorithm compares to the current algorithm, both were run in parallel during the December 2022 – May 2023 period. The two algorithms are compared to Automated Surface Observing System (ASOS) clear sky conditions and reported precipitation. The new algorithm has a higher probability of detection than the current algorithm for all types of ASOS reported precipitation. Several case studies are pulled from the six-month period, showcasing the new algorithm’s improvements. Light precipitation echo continues to be a challenge for QC algorithms, but the new algorithm improves upon the current algorithm.