• Over 1000 HWRF runs for the Eastern North Pacific and Atlantic basins, for the 2008, 2009, and 2010 seasons were conducted in order to produce a robust Reference Configuration of the community code (HWRF PS:85.98.98.88.88.2.4, nicknamed HNR2).

    • Track errors for HNR2 increase linearly with time from near zero at initialization time to 280 nm at the 5-day forecast.

    • A negative intensity bias is noted for HNR2 at all lead times, with a marked increase in errors in the first 6-h of the forecast, suggesting a problem with the initialization. More recent results, not presented here, indicate that this problem has been mitigated in more recent HWRF configurations.

    • Absolute intensity errors increase sharply in the first 6-h of forecast and then grow slowly out to 3-days, after which they remain virtually unchanged.

    • The forecast storm size is larger than the observed one for the 34-, 50-, and 64-kt wind radii, with the worst errors occurring for the 34-kt radii.

    • The worst track and absolute intensity forecasts (outliers) were identified so that forecast improvements for these poorly performing cases can be addressed in the future. These results are included in the Final Report.

    • Model output files have been archived and are available to the community for future studies.