Preliminary evaluation of realtime predictions with WRF LES using UAS and surface-based remote-sensing data collected during 2018 ISARRA Flight Week

The WRF model was configured to run as an LES model (with 100 m resolution) over the northern half of the San Luis Valley of Colorado to support Lower Atmospheric Process Studies at Elevation - a Remotely-piloted Aircraft Team Experiment (LAPSE-RATE) or ISARRA Flight Week. WRF-LES was run twice per day over a 19 day period leading up to and including ISARRA Flight Week which took place 14-20 July 2018. Forecasts were made available in realtime to help guide next-day planning of flight operations. The long-range WRF-LES forecasts were produced by downscaling the 24-36 hour forecasts from the NCEP GFS model. An additional WRF-LES run was used to downscale 6-18 hour forecasts of the 3km resolution NCEP High Resolution Rapid Refresh (HRRR). Both downscaled WRF-LES simulations were valid between 10 and 22 UTC each day in order to support UAS flight planning and operations and to facilitate comparisons of the performance characteristics of the two WRF-LES runs driven with different boundary conditions. Temperature, humidity and wind data collected by UAS flown during ISARRA but several university teams will be used to evaluate model skill. Some UAS sampled 3D winds and/or turbulent fluxes which will be invaluable for evaluating model turbulence forecasts. Sounding data from two sounding systems will also be used to assess the modeled boundary layer. In addition, continuous wind profiles from two CU Doppler lidar (3D wind profiles) and winds, temperature and humidity obtained from the NSSL/Oklahoma University CLAMPS sounding system will be used to evaluate the temporal evolution of the lower atmosphere at two disparate locations in the valley. Sensitivity studies will be performed to assess new physics treatments that are under development to improve the WRF LES simulations.