The African Monsoon Recent Evolution and Current Status Include Week-1 and Week-2 Outlooks

1. The African Monsoon Recent Evolution and Current StatusInclude Week-1 and Week-2 Outlooks Update prepared by Climate Prediction Center / NCEP 22 October 2012 For more information, visit: http://www.cpc.ncep.noaa.gov/products/Global_Monsoons/African_Monsoons/precip_monitoring.shtml

2. Outline • Highlights • Recent Evolution and Current Conditions • NCEP GEFS Forecasts • Summary

3. Highlights:Last 7 Days • Remnants of tropical storm Anais resulted in above average rainfall over portions of Madagascar. • Rainfall deficits were observed over portions of Central and East Africa. • Week-1 outlooks call for an increased chance for above-average rainfall over western Equatorial Africa and portions of the Greater Horn of Africa countries.

4. Rainfall Patterns: Last 7 Days During the past seven days, above-average rainfall was observed over portions of Algeria, local areas in Mali, Guinea, Cote d’Ivoire and Ghana, portions of Nigeria, eastern Cameroon, northern CAR, local areas in Gabon, eastern DRC, southern Uganda, local areas in southern Ethiopia, northern Kenya and southern Somalia, southern Zimbabwe, portions of South Africa and Madagascar. In contrast, portions of Cameroon, Gabon and Congo, many parts of DRC, northern Angola, southern DRC, South Sudan and the neighboring portions of Sudan, portions of Ethiopia and local areas in Somalia and eastern Kenya had below average rainfall.

5. Rainfall Patterns: Last 30 Days During the past 30 days, above-average rainfall was observed over southern Mauritania, portions of Senegal and Mali, Guinea, Sierra Leone, Liberia, much of Cote D’Ivoire, portions of Burkina Faso, Ghana, Benin, local areas in Niger, much of Nigeria, Cameroon and Gabon, portions of CAR, Congo and Angola, portions of DRC and Ethiopia, local areas in Uganda, central Kenya and southern Somalia. In contrast, local areas in Burkina Faso, central Benin, northern Nigeria, southern Chad, portions of CAR, South Sudan, and portions of DRC and Ethiopia had below average rainfall.

6. Rainfall Patterns: Last 90 Days During the past 90 days, southern Mauritania, portions of Senegal, much of Guinea, Guinea-Bissau, Sierra Leone, Mali and Burkina Faso, portions of Liberia and Nigeria, local areas in Niger, southern Chad, northern Cameroon, portions of CAR and DRC, South Sudan, local areas in Angola, northern Uganda, western Kenya, portions of Ethiopia and eastern South Africa had above average rainfall. In contrast, rainfall was below average over eastern Ghana, Togo, local areas in Nigeria, southern Cameroon, portions of DRC, northeastern Ethiopia and Eritrea.

7. Rainfall Patterns: Last 180 Days During the past 180 days, rainfall was above-average over local areas in Senegal, southern Mauritania, many parts of Mali, Guinea Bissau, Guinea, Sierra Leone, local areas in Cote d’Ivoire, Burkina Faso, local areas in Ghana and Benin, portions of Nigeria and Niger, southern Chad, northern Cameroon, portions of CAR, portions of Gabon and DRC, South Sudan, Uganda, western Kenya, local areas in Ethiopia and eastern South Africa. Eastern Liberia, southern Cote d’Ivoire, southern Benin, portions of Nigeria, southern Cameroon, Equatorial Guinea, northern Gabon, portions of Ethiopia and Eritrea had below average rainfall.

8. Recent Rainfall Evolution Daily evolution of rainfall over the last 90 days at selected stations reflects moderate to heavy rains that sustained moisture surpluses over Gabon (bottom panel – left). Tropical Storm Anais associated rainfall helped to erode some of the rainfall deficits over Madagascar. Seasonal total rainfall remained below average due to the recent rainfall decrease over portions of western Ethiopia (top panel – right).

9. Atmospheric Circulation:Last 7 Days The 850hPa wind anomaly (left panel) featured anomalous lower level westerly flow across the Gulf of Guinea and anomalous lower level cyclonic shear near Madagascar, which may have contributed to the observed above average rainfall in their respective regions.

10. NCEP GEFS Model ForecastsNon-Bias Corrected Probability of precipitation exceedance Week-1: Valid 23 – 29 October 2012Week-2: Valid 30 October – 05 November 2012 For week-1 (left panel) and week-2 (right panel), there is an increased chance for rainfall to exceed 50 mm across western and central parts of Equatorial Africa. There is also increased chance for heavy rainfall over portions of Angola.

11. Experimental Week-1 Precipitation Outlooks 23 – 29 October 2012 • There is an increased chance for above-average rainfall over coastal areas of Nigeria, Cameroon, Equatorial Guinea, Gabon, and Congo: The projected phase of the MJO is expected to enhance rainfall in the region. Confidence: Moderate • There is an increased chance for above-average rainfall over eastern Ethiopia, Somalia, and northeastern Kenya: Anomalous lower-level convergence and the projected phase of the MJO are expected to enhance rainfall in the region. Confidence: Moderate

12. Experimental Week-2 Precipitation Outlooks 30 October – 05 November 2012 • There is an increased chance for above-average rainfall over South Africa, Lesotho, and portions of southern Botswana: Anomalous low-level convergence is expected to enhance rainfall in the region. Confidence: Moderate

13. Summary During the past seven days, above-average rainfall was observed over portions of Algeria, local areas in Mali, Guinea, Cote d’Ivoire and Ghana, portions of Nigeria, eastern Cameroon, northern CAR, local areas in Gabon, eastern DRC, southern Uganda, local areas in southern Ethiopia, northern Kenya and southern Somalia, southern Zimbabwe, portions of South Africa and Madagascar. In contrast, portions of Cameroon, Gabon and Congo, many parts of DRC, northern Angola, southern DRC, South Sudan and the neighboring portions of Sudan, portions of Ethiopia and local areas in Somalia and eastern Kenya had below average rainfall. During the past 30 days, above-average rainfall was observed over southern Mauritania, portions of Senegal and Mali, Guinea, Sierra Leone, Liberia, much of Cote D’Ivoire, portions of Burkina Faso, Ghana, Benin, local areas in Niger, much of Nigeria, Cameroon and Gabon, portions of CAR, Congo and Angola, portions of DRC and Ethiopia, local areas in Uganda, central Kenya and southern Somalia. In contrast, local areas in Burkina Faso, central Benin, northern Nigeria, southern Chad, portions of CAR, South Sudan, and portions of DRC and Ethiopia had below average rainfall. During the past 90 days, southern Mauritania, portions of Senegal, much of Guinea, Guinea-Bissau, Sierra Leone, Mali and Burkina Faso, portions of Liberia and Nigeria, local areas in Niger, southern Chad, northern Cameroon, portions of CAR and DRC, South Sudan, local areas in Angola, northern Uganda, western Kenya, portions of Ethiopia and eastern South Africa had above average rainfall. In contrast, rainfall was below average over eastern Ghana, Togo, local areas in Nigeria, southern Cameroon, portions of DRC, northeastern Ethiopia and Eritrea. Week-1 outlooks call for an increased chance for above-average rainfall over southeastern Ethiopia, Somalia, northeastern Kenya, portions of South Africa and Lesotho. In contrast, there is an increased chance for below-average rainfall over South Sudan and the neighboring portions of Uganda, Ethiopia and Kenya.