The Accuracy of Wind and Wave Forecasts

Statistics compiled by the UK Met Office for the verification of offshore wind and wave forecasts have been collated and presented here to show the main seasonal and geographical variations in waters around the UK.

For risk analysis purposes, it is useful to know the likelihood of a specified threshold being exceeded, when a forecast below that threshold has been made.

Therefore, the raw verification statistics have been converted to probabilities of threshold exceedance, as a function of forecast period out to 120 hours.

The relative importance of RMS error and bias is discussed, and examples given.

The contribution to forecast accuracy made by the additional input of the human forecaster to the guidance provided by the numerical forecast model is assessed and quantified.