1. The African Monsoon Recent Evolution and Current Status Include Week-1 and Week-2 Outlooks Update prepared by Climate Prediction Center / NCEP 10 August 2015 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 Above-average rainfall was observed over many places in the Sahel region, whereas suppressed rainfall prevailed across portions of the Gulf of Guinea countries. Week-1 outlooks call for an increased chance for above-average rainfall across southern Senegal, Guinea, Guinea-Bissau, Sierra Leone, southern and central Mali, Burkina Faso, portions of northern Cote d'Ivoire and northern Ghana. In contrast, there is an increased chance for below-average rainfall across Southern Sudan, South Sudan Republic, western Uganda and northeastern DRC.

4. Rainfall Patterns: Last 7 Days During the past seven days, above-average rainfall was observed over portions of Senegal and Mauritania, much of Mali, Guinea, Burkina Faso, northern Ghana, northern Togo, northern Benin, Niger, local areas in Nigeria, portions of Chad and Cameroon, CAR, portions of South Sudan Republic, local areas in western and eastern Sudan, portions of Ethiopia, and local areas in DRC. In contrast, local areas in southern Mali, portions of Sierra Leone, Liberia and Cote d’Ivoire, southern Ghana, southern Togo, southern Benin, southern Nigeria, western Cameroon, and portions of central Sudan had below-average rainfall.

5. Rainfall Patterns: Last 30 Days During the past 30 days, rainfall was rainfall was above-average over portions of southern Mauritania, Senegal, Gambia, many parts of Mali, Guinea-Bissau, Guinea-Conakry, Sierra Leone, Liberia, local areas in Cote d’Ivoire and Ghana, Burkina Faso, northern Togo, northern Benin, northern Nigeria, Niger, Cameroon, western CAR, southern Chad, local areas in Sudan, and portions of South Sudan Republic Ethiopia. In contrast, below-average rainfall was observed over portions of Cote d’Ivoire, southern Ghana, southern Togo, southern Benin, portions of Nigeria, local areas in Cameroon, parts of Gabon and Congo-Brazzaville, northern DRC, central and eastern Chad, portions of CAR Sudan, northern South Sudan Republic, Eritrea, and northeastern Ethiopia.

6. Rainfall Patterns: Last 90 Days During the past 90 days, rainfall was above-average over portions of southern Mauritania, much of Mali, portions of Senegal, Guinea-Conakry, Sierra Leone, Liberia, portions of Cote d’Ivoire, Burkina Faso, portions of Niger and western Chad, portions of Cameroon, western Gabon, CAR, South Sudan Republic, southern Sudan, portions of DRC, Uganda, many parts of Ethiopia, local areas in Kenya, and parts of northern Somalia. In contrast, local areas in Senegal, portions of Cote d’Ivoire, Ghana, Togo, Benin, Nigeria, local areas in Cameroon, eastern Gabon, Congo Brazzaville, eastern Chad, southern Sudan, portions of DRC, Eritrea, local areas in Ethiopia, and portions of Somalia and Kenya had below-average rainfall.

7. Rainfall Patterns: Last 180 Days During the past 180 days, rainfall was above-average over portions of Senegal and southern Mauritania, much of Guinea-Conakry, Sierra Leone, Liberia, Mali, Burkina Faso, Cote d’Ivoire, southern Ghana, Niger, portions of Chad, many parts of CAR, western Gabon, northern Congo- Brazzaville, much of DRC, South Sudan Republic, southern Sudan, Somalia, portions of Ethiopia, Zambia, northern Mozambique, portions of Botswana and Zimbabwe, and Madagascar. In contrast, local areas in Senegal, portions of Ghana, Togo, Benin, much of Nigeria, portions of Cameroon, Angola, Namibia, South Africa, southern and central Mozambique, Malawi, portions of Tanzania, local areas in DRC, northern Kenya and portions of Ethiopia had below-average rainfall.

8. Recent Rainfall Evolution Daily evolution of rainfall over the last 90 days at selected places reflects that moderate to heavy rainfall maintained above-average rainfall over portions of Senegal (bottom left) and helped to erode accumulated rainfall deficits over parts of Niger (bottom right). In contrast, seasonal total rainfall remained below-average over portions of eastern Sudan (top right).

9. Atmospheric Circulation: Last 7 Days The 200hpa wind anomalies (right panel) featured upper-level anti-cyclone over Northeast Africa, and a broad area of westerly flow across many places in the Sahel region and the Greater Horn of Africa.

10. NCEP GEFS Model Forecasts Non-Bias Corrected Probability of precipitation exceedance Week-1: Valid 11 – 17 Aug 2015 Week-2: Valid 18 – 24 Aug 2015 For week-1 (left panel) and week-2(right panel), there is an increased chance for rainfall to exceed 50 mm over portions of Senegal, Gambia, Guinea-Bissau, Guinea-Conakry, Sierra Leone, portions of Liberia, northern Cote d’Ivoire, southern Mali, Ghana, northern Togo, Benin, Nigeria, Cameroon, Chad, and western Ethiopia.

11. Week-1 Precipitation Outlooks 11 – 17 August, 2015 1.There is an increased chance for above-average rainfall across southern Senegal, Guinea, Guinea-Bissau, Sierra Leone, southern and central Mali, Burkina Faso, portions of northern Cote d'Ivoire and northern Ghana: A broad area of anomalous lower-level convergence and upper-level divergence is expected to enhance rainfall in the region. Confidence: Moderate 2.There is an increased chance for below-average rainfall across Southern Sudan, South Sudan, western Uganda and northeastern DRC: Anomalous lower-level easterly flow in the Congo Air Boundary area, combined with upper- level divergence is expected to suppress rainfall in the region. Confidence: Moderate

12. Week-2 Precipitation Outlooks 18 – 24 August, 2015 1.There is an increased chance for above-average rainfall over Guinea, Guinea-Bissau, Gambia, southern Senegal, southern Mali, Northern Liberia, Burkina Faso, northern Cote d‘Ivoire, Ghana, and northwestern Nigeria: A broad area of anomalous lower-level convergence and upper-level divergence 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 Senegal and Mauritania, much of Mali, Guinea, Burkina Faso, northern Ghana, northern Togo, northern Benin, Niger, local areas in Nigeria, portions of Chad and Cameroon, CAR, portions of South Sudan Republic, local areas in western and eastern Sudan, portions of Ethiopia, and local areas in DRC. In contrast, local areas in southern Mali, portions of Sierra Leone, Liberia and Cote d’Ivoire, southern Ghana, southern Togo, southern Benin, southern Nigeria, western Cameroon, and portions of central Sudan had below-average rainfall. During the past 30 days, rainfall was rainfall was above-average over portions of southern Mauritania, Senegal, Gambia, many parts of Mali, Guinea-Bissau, Guinea-Conakry, Sierra Leone, Liberia, local areas in Cote d’Ivoire and Ghana, Burkina Faso, northern Togo, northern Benin, northern Nigeria, Niger, Cameroon, western CAR, southern Chad, local areas in Sudan, and portions of South Sudan Republic Ethiopia. In contrast, below-average rainfall was observed over portions of Cote d’Ivoire, southern Ghana, southern Togo, southern Benin, portions of Nigeria, local areas in Cameroon, parts of Gabon and Congo- Brazzaville, northern DRC, central and eastern Chad, portions of CAR Sudan, northern South Sudan Republic, Eritrea, and northeastern Ethiopia. During the past 90 days, rainfall was above-average over portions of southern Mauritania, much of Mali, portions of Senegal, Guinea-Conakry, Sierra Leone, Liberia, portions of Cote d’Ivoire, Burkina Faso, portions of Niger and western Chad, portions of Cameroon, western Gabon, CAR, South Sudan Republic, southern Sudan, portions of DRC, Uganda, many parts of Ethiopia, local areas in Kenya, and parts of northern Somalia. In contrast, local areas in Senegal, portions of Cote d’Ivoire, Ghana, Togo, Benin, Nigeria, local areas in Cameroon, eastern Gabon, Congo Brazzaville, eastern Chad, southern Sudan, portions of DRC, Eritrea, local areas in Ethiopia, and portions of Somalia and Kenya had below-average rainfall. Week-1 outlooks call for an increased chance for above-average rainfall across southern Senegal, Guinea, Guinea-Bissau, Sierra Leone, southern and central Mali, Burkina Faso, portions of northern Cote d'Ivoire and northern Ghana. In contrast, there is an increased chance for below-average rainfall across Southern Sudan, South Sudan Republic, western Uganda and northeastern DRC.