An Evaluation of the WRF Model Simulations from the WWMPP Using Observations

Numerical modeling has been both an innovative and integral part of the Wyoming Weather Modification Pilot Project (WWMPP). The Real-time Four Dimensional Data Assimilation (RT-FDDA) model was run in real time during every season of the program and utilized as a forecast model by the WWMPP forecasters to help call seeding cases. In addition, the WRF model coupled with a new silver iodide (AgI) cloud seeding parameterization was utilized to simulate seeding cases to aid in the evaluation and interpretation of the statistical seeding experiment. In order to assess the performance of these model simulations, they need to be compared against observations. Sounding data from sondes released at the beginning of each seeding case were utilized to evaluate the modeled thermodynamic structure, in particular temperature and winds at 700 mb, which were key components to identifying optimal seeding conditions. Another key component for seeding was the amount of supercooled liquid water available, which was assessed with radiometer measurements of Liquid Water Path (LWP) and compared to the LWP from the model. Finally, the model's precipitation forecasts were also assessed using precipitation gauge data from both SNOTEL gauges and the high-resolution gauges deployed for the WWMPP. Results of this model evaluation will be presented.