Summary: Precipitation Evaluation

Validation of model skill requires attention be placed on the quality and uncertainty contained in observational data sets

In regions of complex terrain, models should be verified on their native grids with minimal postprocessing

Objective skill measures should be consistent with subjective, visual evaluations. The ETS may be misleading in some instances, since overforecasting precipitation is rewarded while slight underforecasting is penalized.

Models that resolve the terrain of the western United States tend to have higher skill during winter for moderate-to-large precipitation totals. Less skill is evident during spring.

Skill for coarse resolution models improves if model precipitation is readjusted across grid squares to conform to monthly PRISM climatology

Forecast skill is higher along West Coast than over Intermountain region