Enhancing Severe Weather Prediction with Microwave All-Sky Radiance Assimilation: The 10 August 2020 Midwest Derecho

In this study, we assimilated microwave (MW) all-sky radiances from low-Earth-orbiting satellites and examined their impact on the analyses and forecasts of surface wind gusts associated with the 10 August 2020 Midwest derecho. Compared with the baseline that assimilated conventional surface and upper-air observations and infrared (IR) all-sky radiances from geostationary satellites, the addition of MW all-sky radiances improved the analyzed and forecasted convection-stratiform structures of the derecho. Results show that MW all-sky radiances provided additional information, compared with IR radiances, on hydrometeors within the storm, leading to improved forecasts out to 2 hr with quantitatively more accurate surface gusts. This is the first study to assimilate MW all-sky radiances for a severe weather event using a convection-permitting numerical weather prediction model (our model resembles NOAA's High-Resolution Rapid Refresh), and the results suggest promising avenues for improving severe weather forecasts worldwide in the future.