For this presentation three cases will be highlighted (13 November 2015, 17 November 2015, and 8-9 December 2015). All three events were heavy precipitation events (100-300 mm over lower windward/southwest slope) associated with an atmospheric river extending from the eastern Pacific to the Pacific Northwest. Freezing levels were relatively high (~2 km ASL), so these events were used to evaluate the riming and cloud water accretional growth in the various WRF microphysical schemes. The WRF was nested down to 1-km grid spacing using the Rapid Refresh (RR) analyses for initial and boundary conditions for a relatively short 36-h simulation. Four different microphysical schemes were evaluated using surface gauge, ground radars (DOW, NPOL, and WSR-88D), and aircraft (Citation): the new predicted particle properties (P3) scheme, WSM6, Thompson, and YLin-Stony Brook schemes. This presentation will highlight some of windward flow and precipitation structures between the observations and WRF. The importance of properly simulating the partition between rimed and unrimed snow will be discussed as well as potential challenges in simulating the upstream moisture flux as demonstrated by using a few other analyses for initial/boundary conditions.