Forecast Verification Activities

This page contains links to research results related to the verification of hydrologic and streamflow forecasts. Along with much of the field of medium to long range hydrologic forecasting, west-wide forecast system research has recently begun to emphasize and explore approaches for forecast verification. As noted in Welles et al. (2007), a number of forecast verification approaches are in place within the National Weather Service and other forecast agencies, but a systematic hydrologic verification effort (with associated standards) within the hydrology community does not yet exist. This is particularly true for medium-range to long lead hydrologic forecasts, in contrast to flood forecasts, for which forecast verification practices are relatively more mature and widespread.

Aside from the mechanics of statistical skill or accuracy assessment, a particular challenge in this area is to filter or distill the broad set of metrics that are available for describing the performance of a forecast into a smaller subset that are particularly relevant to the decision processes of forecast user communities. Another challenge is to expand this set of relevant metrics to include ones that may be traditionally utilized only by forecasters, but nonetheless communicate important characteristics of the forecasts that would also be meaningful for decisionmakers.

A collaborative, pilot effort to compare UW and National Weather Service forecasts began in summer 2006, and some initial results are posted below. These will be updated and expanded as the effort continues. Our intention is that in addition to the forecast assessments obtained in this effort, the models and datasets from which the results are derived can be provided online for researchers who are interested in collaborating on any aspect of model calibration or forecast production, as well as forecast verification. Website: Ensemble Forecast Comparisons (experimental)

Forecast Verification Links

NWS

References (cited)

Welles,E., S. Soorooshian, G. Carter and B. Olsen, 2007, Hydrologic Verification: A call for action and collaboration, Bull. Amer. Met. Soc. 88:4, 503-511. DOI:10.1175/BAMS-88-4-503

References of published water supply forecast verifications

Franz, K. J., H. C. Hartmann, S. Sorooshian, and R. Bales, 2003: Verification of National Weather Service ensemble streamflow predictions for water supply forecasting in the Colorado River basin. J. Hydrometeor., 4, 1105-1118.

Pagano, T., D. Garen, and S. Sorooshian, 2004: Evaluation of official western U.S. seasonal water supply outlooks, 1922-2002. J. Hydrometeor., 5, 896-909.