Department of Statistics & Statistical LaboratoryIowa State University
RTG Work Group Iowa State RTG Grant

RTG Student Work Group

Probabilistic Prediction from Mixtures of Ensemble Precipitation Forecasts
Jon Hobbs
Abstract • February 6, 2008

Ensembles of numerical weather prediction models provide useful information about the forecast uncertainty for a number of variables, including precipitation. The ensemble predictive distribution typically does not have the desired coverage, but this can be remedied through statistical post-processing. The ensemble forecasts are used as predictors in generalized linear models that describe the distribution of observed precipitation. In addition, models can be combined using Bayesian Model Averaging (BMA), which incorporates model uncertainty by using a weighted average of models, favoring models that have superior predictive performance. This study applies the methodology to an ensemble of 16 models to develop and assess probabilistic precipitation forecasts for lead times of one to five days.