Forecast verification activities for the Sydney 2000 Forecast Demonstration Project

As part of the World Weather Research Pogram Sydney 2000 Forecast Demonstration Project (FDP), an international verification team has been assembled. The team includes verification experts from Australia, Canada, Finland, Germany, the United Kingdom, and the United States. The dual charge to this team is (1) to design verification methods that are appropriate for application to the forecasts produced by the various nowcasting systems and (2) to provide an overall, consistent, evaluation of the forecasts. Prior to the Sydney 2000 FDP, the team identified a set of six questions that should be answered through the verification studies: (1) Is it feasible to predict convective cell locations with enough accuracy and skill to be useful? (2) What are the accuracy and skill of QPF, rainfall rate, and precipitation occurrence as a function of lead time and accumulation period? (3) Is it feasible to predict wind speed and direction at points with enough accuracy and skill to be useful? (4) What is the accuracy of severe thunderstorm wind gust diagnoses and forecasts? (5) What is the accuracy of hail location and size detections and forecasts? and (6) Do the forecasters improve the quality of the forecasts compared to the FDP products alone? Specific approaches also were identified to answer these questions. For example, storm location forecasts will be evaluated using standard grid-to-grid comparisons; in addition, methods to diagnose the sources of errors (e.g., errors in location, intensity) also will be applied. The verification studies will be undertaken once data are consolidated and made available. Regardless of the number of cases that are obtained, the verification demonstration will provide useful insight into the applicability of various approaches to verification of the nowcast products. The activities of the international team also will provide synergy to the development of improved verification methods for phenomena, such as quantitative precipitation forecasts that historically have been difficult to evaluate.