In order to compare the OCSI with other Atlantic Seasonal hurricane outlooks, secondary predictions where made of the number of tropical cyclones, number hurricanes, number of tropical storm days, and number of hurricane days each year. These forecasts were compared to climatology as well as the forecast made by Colorado State Professor Bill Gray. The years used for this comparison were for the twenty years from 1984 to 2003.

This verification of the twenty years of forecast demonstrates that WRC’s OCSI model is as accurate if not more accurate than Gray’s model. The advantage of the OCSI model is that WRC’s model can make a prediction years in advance. Table 1 gives a summary of the forecasts comparisons that are shown in Table 2 through 5. This table gives the number of years that each model was closest within the limits indicated.

WRC forecast the number of storms each year and this forecast was verified for the past 20 years. There were eight years out of the twenty years when WRC’s forecast was within plus or minus one storm. Gray’s forecast was only within one storm five of the twenty years and climatology was only within one storm two of the twenty years. This is shown in Table 2. Figure 1 shows a graph comparing the plus or minus error in the forecast versus observed. This graph also shows the forecast error for the forecast made by climatology.

WRC forecast the number of hurricanes each year. The forecast verified within one hurricane ten out of the twenty years and Gray’s method forecast within one hurricane eight of the twenty years. WRC forecast the number of hurricane days each year. This verified within five days eight out of the twenty years. Table 3 shows the comparison of the forecast erros.

Gray’s method forecast the number of hurricane days within five days six out of the twenty years and climatology was five out of the twenty years. WRC’s model then forecast the number of storm days, this verified within ten days for ten of the twenty years. Gray’s model forecast the number of days within ten days for seven of the twenty years and climatology five out of the twenty years. Table 4 gives the detail of these comparisons.

Table 5 gives the forecast for both WRC’s and Gray’s model for the number of storm days in each year. WRC’s model forecast the number of days within ten days for ten of the twenty years. Gray’s model forecast the number of days within ten days for seven of the twenty years.

This verification of the twenty years of forecast demonstrates that the WRC’ OCSI model is as accurate if not more accurate than Gray’s model. The advantage of the OCSI model is that WRC’s model can make a prediction years in advance. .