The precipitation forecast methodology utilized by the Climate Prediction Center Africa Desk is a statistical technique entitled "Canonical Correlation Analysis" or CCA for short. In this forecast, quasi-global sea surface temperatures between 40°S and 60°N at a resolution of 10° by 10° latitude-longitude are used to predict rainfall patterns over the area and season of specific interest. The predictions are expressed in terms of tilting of the odds favoring the categories of above, near, or below rainfall. The climatological probability of each of the three categories, above, near, or below average rainfall is 100% divided by 3 or 33%. The probability for the near average category remains fixed at 0.33 because CCA has virtually no skill in predicting this category. The tilting of the odds are presented in units of 5% above or below the average. When forecast skill is low, climatology is suggested. Thus, no forecast is made.
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