Angola + 3 more

CCA guidance for Southern Africa rainfall in Jan-Mar 2003 at one month lead

Originally published

Southern Africa is defined here as the region between 10°S and 35°S; 10-50°E. For more about the CCA technique, see description below. The prediction for Jan-Feb-Mar 2003 southern Africa rainfall at one month lead (see map below) is weak to moderate. Slightly higher than climatological probabilities for below normal rainfall are predicted for most of southern Africa, including northern South Africa, southern Mozambique, Zimbabwe, Namibia, and parts of Botswana, Zambia, and Angola. Slightly higher than climatological probabilities for above normal rainfall are predicted for northern Mozambique. Climatology is suggested elsewhere. Note that the current moderate El Niño event which has been strengthening over the past several weeks appears to have influenced this forecast significantly.

In this forecast, quasi-global SSTs between 40°S and 60°N at a resolution of 10° by 10° lat-lon are used to predict southern African rainfall. The predictions are expressed in terms of departures from climatological probabilities for the two extreme categories above and below-normal rainfall. The climatological probability of each of these categories is 0.33. The probability for the normal category remains fixed at 0.33 because CCA has virtually no skill in predicting this category. When skill is low, climatology is suggested. Thus, no forecast is made.