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 19 September 2016 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 • Rainfall surpluses exceeded 100mm over portions of Guinea and Sierra Leone. • Week-1 outlooks call for an increased chance for above-average rainfall over much of the Gulf of Guinea and portions of central Africa countries.

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

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

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

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

8. Recent Rainfall Evolution Daily evolution of rainfall over the last 90 days at selected locations shows sustained moisture surpluses over parts of Sierra Leone(bottom left) and western Ethiopia (top right). In contrast, seasonal total rainfall remained below-average over parts of Uganda(bottom right).

9. Atmospheric Circulation:Last 7 Days The 700 hPa (left panel) wind anomalies featured a broad area of westerlies across the Gulf of Guinea region.

10. NCEP GEFS Model ForecastsNon-Bias Corrected Probability of precipitation exceedance Week-1: Valid 20 – 26 September, 2016 Week-2: Valid 27 Sep – 03 Oct, 2016 For week-1 (left panel) and week-2 (right panel), there is an increased chance for weekly rainfall totals to exceed 50mm over many places in the Gulf of Guinea and central Africa countries, and portions of Ethiopia.

11. Week-1 Precipitation Outlooks 20 - 26 September 2016 • There is an increased chance for above-average rainfall over many places in the Gulf of Guinea countries: An area of stronger than normal onshore flow, coupled with anomalous lower-level convergence and upper-level divergence is expected to enhance rainfall in the region. Confidence: Moderate • There is an increased chance for above-average rainfall over portions of Congo Brazzaville, CAR, northern DRC, and South Sudan: An area of anomalous low-level divergence and upper-level convergence is expected to suppress rainfall in the region. Confidence: Moderate

12. Week-2 Precipitation Outlooks 27 Sep – 03 Oct, 2016 • There is an increased chance for above-average rainfall over Guinea-Conakry, Sierra Leone, Cote d’Ivoire, portions of Ghana, Togo, Benin, and Nigeria: An area of stronger than normal onshore flow, coupled with anomalous lower-level convergence and upper-level divergence is expected to enhance rainfall in the region. Confidence: Moderate • There is an increased chance for below-average rainfall over portions of Nigeria, Cameroon, Chad, CAR, and southwestern Sudan: An area of anomalous lower-level divergence and upper-level convergence is expected to suppress rainfall in the region. Confidence: Moderate • There is an increased chance for above-average rainfall over southern Zimbabwe, eastern South Africa, and southern Mozambique: Anomalous lower-level cyclonic circulation is expected to enhance rainfall in the region. Confidence: Moderate • There is an increased chance for above-average rainfall over across northern Somalia and Djibouti: An area of anomalous lower-level convergence is expected to enhance rainfall in the region. Confidence: Moderate

13. Summary • During the past seven days, rainfall was above-average over local areas in Mauritania and Senegal, Guinea-Bissau, Guinea-Conakry, Sierra Leone, parts of Liberia, southwestern Mali, local areas in Cote d’Ivoire, parts of Burkina Faso, local areas in Ghana, portions of Niger and Benin, local areas in Nigeria, Cameroon, CAR, Congo-Brazzaville, local areas in Angola and DRC, southern and eastern Sudan, western Ethiopia, portions of South Sudan and Uganda. In contrast, local areas in Cote d’Ivoire and Ghana, portions of Nigeria, southern Chad, local areas in CAR, portions of DRC, and local areas in eastern Ethiopia had below-average rainfall. • During the past 30 days, rainfall was above-average over many places in Mauritania, much of Senegal, Guinea, many places in Mali, Sierra Leone, Liberia, Cote d’Ivoire, Burkina Faso, central and southern Ghana, Togo, northern Benin, local areas in Niger, southern and eastern Nigeria, Cameroon, local areas in Chad, Equatorial Guinea, northern and eastern Gabon, Congo-Brazzaville, CAR, portions of DRC, parts of South Sudan, western Eritrea, and portions of Sudan and western Ethiopia. In contrast, local areas in central Senegal, Guinea-Bissau, coastal Liberia, local areas in Ghana and Benin, northcentral Nigeria, portions of Chad, eastern and southern DRC, much of Uganda, eastern South Sudan, western Kenya, and portions of Ethiopia had below-average rainfall. • During the past 90 days, rainfall was above-average over many parts of Mauritania, Senegal, Guinea-Bissau, Guinea-Conakry, Sierra Leone, much of Liberia and Cote d’Ivoire, Mali, Burkina Faso, Niger central and northern Ghana, much of Togo and Benin, portions of Nigeria, Cameroon, CAR, southern and central Chad, much of South Sudan, southern and eastern Sudan, Equatorial Guinea, local areas in Gabon, Congo Brazzaville, portions of DRC, many parts of Ethiopia, Eritrea, portions of western Kenya, local areas in Angola, and portions of South Africa. In contrast, below-average rainfall was observed over local areas in southeastern Cote d’Ivoire, southern Ghana, costal Togo and Benin, northcentral Nigeria, local areas in southern Cameroon, portions of DRC, much of Uganda, portions of northern Tanzania and western Kenya, and portions of southern Ethiopia. • Week-1 outlooks call for an increased chance for above-average rainfall over much of the Gulf of Guinea and portions of central Africa countries.