We’ve looked at both model forecasts. Now we’ll use the Extreme Forecast Index or EFI to evaluate the ECMWF forecasts.
EFI is a predictive parameter used to assess the abnormality of a forecast weather situation based on the difference between the ECMWF ensemble prediction system distribution and the ECMWF model’s climatology. The EFI is produced for maximum significant wave height and other parameters.
The EFI uses values from -1 to +1.
EFI magnitudes of 0.5 to 0.8 (irrespective of sign) generally signify that "unusual" weather is likely. Magnitudes above 0.8 usually signify that "very unusual" weather is likely.