We focus on improving our understanding of why regional numerical weather prediction (NWP) models often fall short of predicting accurate snow totals via a case study that occurred on February 22-24, 2017. High-resolution simulations are run using the Weather Research and Forecasting (WRF) model. Four different microphysics parameterizations are utilized in this study: Thompson, Morrison two-moment, Predicted Particle Properties (P3), and the WRF Single-Moment 6-Class Scheme; the coupling between cloud properties and radiation as well as the role of latent heat release due to individual microphysical processes are also explored. The simulated precipitation is compared with both SNOTEL and PRISM data to quantify model errors and improvements using higher-resolution simulations and advanced microphysical parameterization.
The results support past studies which suggest that a dependency exists regarding the choice of microphysics parameterization and resolution over this region. All of the parameterizations utilized in this study overpredict snowfall accumulation; no clear bias as a function of altitude is identified. The coupling between the cloud microphysics and radiation is also found to have a minimal impact on storm strength, storm track, and snowfall amounts. Lastly, certain microphysical processes and the resultant latent heating are found to affect the storm characteristics.