Navigators use routing software to figure out where to go and how to get to the finish line first. When a routing software platform (e.g., the Expedition software) generates an optimal route it applies the boat’s performance files (commonly known as polars or VPPs) to the weather forecast GRIB files. Sailing teams invest heavily into refining and perfecting the boat’s polars, but when it comes to the GRIB file, we’re left to choose which source we think is best, what was recommended, or even our own bias for GRIBs we’ve paid for from a private forecaster. Everyone who makes a GRIB file (e.g., PredictWind, GFS, COAMPS, EC, etc.) think they produce the best file. To put this in perspective, within the Expedition software it is possible to download nearly 75 different types, resolutions, and sources of weather forecast GRIB files at various locations around the world. How would you choose which is the best one and most accurate? That’s where Model Accuracy comes in.