Relative Skill of IFS Models

It is important to have measures of both forecast skill and relative differences in error of HRES, ensemble control, ensemble mean, and individual ensemble members.  This allows the forecaster to assess the strength of one product over another and the way this varies through the forecast period.  The Anomaly Correlation Coefficient (ACC) and the Equitable Threat Score (ETS) show the comparative performances on a global scale.   The relative differences in error with lead-time show comparative errors with lead-time.  Verification results suggest HRES provides better detail, at least at shorter lead-times, but becomes less precise later.   Relative weights can be assigned to HRES and ENS at different lead-times to better use the strengths of each in a more structured way.