Gridded Verification of PoPs (Probability of Precipitation) over the Complex Terrain of Eastern Washington and Northern Idaho

摘要

The verification of Probability of Precipitation (PoPs) has always been nebulous topic and up until recently has only been done at point locations. While some insight into point biases could be gained from this method, there was always a question as to whether this was representative of a larger area. With the advent of BOIVER, we can now ascertain PoP biases over our entire forecast domain and how it relates to the complex terrain of eastern Washington and north Idaho. For this study we will take a look at two distinct synoptic patterns and their corresponding PoP biases over the forecast area. One pattern featured a typical wintertime zonal or westerly flow pattern. The other pattern featured a prolonged northwest flow regime more dominated by a long wave ridge centered over the region.