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 09 May 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 • An other week of moderate to heavy rainfall sustained moisture surpluses over many places in the Greater Horn of Africa, whereas below-average rainfall continued to prevail over much of the Gulf of Guinea region. • Week-1 outlooks call for an increased chance for above-average rainfall over Cameroon, Equatorial Guinea, Gabon, parts of Congo-Brazzaville, eastern DRC, Uganda, southwestern Kenya, and portions of Ethiopia and northern Somalia. In contrast, there is an increased chance for below-average rainfall over portions of Cote d’Ivoire, Ghana, Togo, Benin, Nigeria, and central DRC.

4. Rainfall Patterns: Last 7 Days During the past seven days, above-average rainfall was observed over portions of central Guinea, Sierra Leone, northwestern Ghana, Equatorial Guinea, Gabon, southern Congo, parts of CAR, South Sudan Republic, parts of northern DRC, many parts of Ethiopia, Somalia, Uganda, portions of Kenya, and local areas in Tanzania. In contrast, weekly total rainfall was below-average over Liberia, Cote D’Ivoire, portions of Ghana, Togo, Benin, Nigeria, parts of Cameroon, and local areas in southern Ethiopia and southern Kenya.

5. Rainfall Patterns: Last 30 Days During the past 30 days, rainfall was above-average over portions of Guinea Burkina Faso, Togo, local areas in northwestern Nigeria, eastern Cameroon, CAR, South Sudan, Equatorial Guinea, Gabon, much of Congo Brazzaville, portions DRC, Uganda, much of Ethiopia and Somalia, Djibouti, Tanzania, northwestern Angola, eastern Zimbabwe, northern Malawi, local areas in Mozambique, and parts of Madagascar. In contrast, below-average was observed over Liberia, much of Cote d’Ivoire, southern Ghana, much of Nigeria, portions of Angola, portions of DRC, portions South Africa, local areas in Kenya and Tanzania, and portions of Madagascar.

6. Rainfall Patterns: Last 90 Days During the past 90 days, rainfall was above-average over portions of Guinea, coastal Cote d’Ivoire, Burkina Faso, western Niger, Ghana, Togo, Benin, local areas in Nigeria, Cameroon, CAR, South Sudan, parts of Gabon, Congo Brazzaville, northern DRC, much of Ethiopia, northern Somalia, Kenya, Tanzania, northern Mozambique, northern Madagascar, western Zambia, Zimbabwe, Botswana, eastern Namibia, and southern South Africa. In contrast, below-average rainfall was observed over parts of eastern Guinea Conakry, Liberia, Cote d’Ivoire, southern Ghana, Angola, southern and eastern DRC, Namibia, local areas in southern Ethiopia, local areas in Kenya and Somalia, Uganda, eastern Zambia, southern Malawi, Mozambique, South Africa, and portions of Madagascar.

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

8. Recent Rainfall Evolution Daily evolution of rainfall over the last 90 days at selected locations shows sustained rainfall deficits over parts of Ghana (bottom left). Moderate to heavy rainfall helped to erode accumulated rainfall deficits over parts of Uganda (bottom right). Seasonal total rainfall remained above-average over parts of eastern Ethiopia (top right).

9. Atmospheric Circulation:Last 7 Days An area of lower-level wind convergence across the greater Horn of Africa may have contributed to the observed above-average rainfall in the region.

10. NCEP GEFS Model ForecastsNon-Bias Corrected Probability of precipitation exceedance Week-1: Valid 10 – 16 May, 2016 Week-2: Valid 17 – 23 May, 2016 For week-1 (left panel) and week-2 (right panel), there is an increased chance for weekly rainfall totals to exceed 50 mm over local areas in Nigeria, Cameroon and Gabon, northeastern DRC, portions of Kenya and Ethiopia.

11. Week-1 Precipitation Outlooks • There is an increased chance for below-average rainfall over portions of Cote d’Ivoire, Ghana, Togo, Benin, and Nigeria: Weaker than normal monsoon flow, combined with anomalous upper-level convergence is expected to suppress rainfall in the region. Confidence: Moderate • There is an increased chance for above-average rainfall across Cameroon, Equatorial Guinea, Gabon, and parts of Congo-Brazzaville: An area of stronger than normal monsoon flow from the Atlantic Ocean, 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 central DRC: A broad area of anomalous lower-lever divergence and upper-level convergence is expected to suppress rainfall l in the region. Confidence: Moderate • There is an increased chance for above-average rainfall over portions of eastern DRC, Uganda, and southwestern Kenya: An area of anomalous lower-level convergence is expected to enhance rainfall in the region. Confidence: Moderate • There is an increased chance for above-average rainfall over portions of Ethiopia and northern Somalia: An area of anomalous lower-level convergence and upper-level divergence is expected to enhance rainfall in the region. Confidence: Moderate 10 – 16 May, 2016

12. Week-2 Precipitation Outlooks 17 – 23 May, 2016 • There is an increased chance for below-average rainfall over the central portions of the DRC: Anomalous lower-level divergence, coupled with upper-level convergence is expected to suppress rainfall in the region. Confidence: Moderate • There is an increased chance for above-average rainfall over parts of western Kenya, eastern South Sudan, and western Ethiopia: Anomalous lower-level convergence, combined with 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 central Guinea, Sierra Leone, northwestern Ghana, Equatorial Guinea, Gabon, southern Congo, parts of CAR, South Sudan Republic, parts of northern DRC, many parts of Ethiopia, Somalia, Uganda, portions of Kenya, and local areas in Tanzania. In contrast, weekly total rainfall was below-average over Liberia, Cote D’Ivoire, portions of Ghana, Togo, Benin, Nigeria, parts of Cameroon, and local areas in southern Ethiopia and southern Kenya. • During the past 30 days, rainfall was above-average over portions of Guinea Burkina Faso, Togo, local areas in northwestern Nigeria, eastern Cameroon, CAR, South Sudan, Equatorial Guinea, Gabon, much of Congo Brazzaville, portions DRC, Uganda, much of Ethiopia and Somalia, Djibouti, Tanzania, northwestern Angola, eastern Zimbabwe, northern Malawi, local areas in Mozambique, and parts of Madagascar. In contrast, below-average was observed over Liberia, much of Cote d’Ivoire, southern Ghana, much of Nigeria, portions of Angola, portions of DRC, portions South Africa, local areas in Kenya and Tanzania, and portions of Madagascar. • During the past 90 days, rainfall was above-average over portions of Guinea, coastal Cote d’Ivoire, Burkina Faso, western Niger, Ghana, Togo, Benin, local areas in Nigeria, Cameroon, CAR, South Sudan, parts of Gabon, Congo Brazzaville, northern DRC, much of Ethiopia, northern Somalia, Kenya, Tanzania, northern Mozambique, northern Madagascar, western Zambia, Zimbabwe, Botswana, eastern Namibia, and southern South Africa. In contrast, below-average rainfall was observed over parts of eastern Guinea Conakry, Liberia, Cote d’Ivoire, southern Ghana, Angola, southern and eastern DRC, Namibia, local areas in southern Ethiopia, local areas in Kenya and Somalia, Uganda, eastern Zambia, southern Malawi, Mozambique, South Africa, and portions of Madagascar. • Week-1 outlooks call for an increased chance for above-average rainfall over Cameroon, Equatorial Guinea, Gabon, parts of Congo-Brazzaville, eastern DRC, Uganda, southwestern Kenya, and portions of Ethiopia and northern Somalia. In contrast, there is an increased chance for below-average rainfall over portions of Cote d’Ivoire, Ghana, Togo, Benin, Nigeria, and central DRC.