RESUME / ABSTRACT  


Ensemble forecasting: Assessing flow dependent variations in predictability


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Zoltan Toth
NCEP





It has been shown that information on uncertainty in weather forecasts can be of critical value in real world applications. Therefore the transition to probabilistic forecasting has become a priority in the US National Weather Service. In general, probabilistic forecasts can be based either on a single Numerical Weather Prediction (NWP) model forecast, enhanced with corresponding verification statistics, or on an ensemble of such forecasts (with or without statistical postprocessing). This presentation will assess the value of the latter, ensemble approach in assessing flow dependent variations in forecast uncertainty that cannot be easily captured by alternative methods.