Introducing and verifying rainfall probability forecasts in a small meteorological office

Abstract

The introduction of a new medium-range weather forecast presented an opportunity to establish a verification procedure for monitoring the reliability and accuracy of probability of precipitation (PoP) forecasts. The need for verification is discussed and a simple verification procedure described, using reliability diagrams as a visual guide to forecaster bias, Brier Scores to give levels of accuracy and Skill Scores to demonstrate skill levels when comparing forecast methods. The application of this verification procedure in a small meteorological office, with no dedicated research facilities, is presented and discussed.