Optimally shifted QPF verification scores

A disadvantage of traditional QPF verification scores is its difficulty in distinguishing small displacement errors from larger ones. We have developed a system in which regional precipitation forecast fields are automatically shifted to locate the best overlap with observed precipitation fields, and QPF statistics are computed for both before and after the shift. Traditional verification scores are displayed alongside the optimally shifted scores, with the optimum shift vectors. This system works well within the traditional QPF verification frame work, the results are simple to understand and give users a more comprehensive picture of overall model QPF performance.

Further details about the system and verification results will be presented at the conference.