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 16 October 2017 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 • Below-average rainfall was observed over portions of the Gulf of Guinea region, whereas many places in central and eastern Africa received above-average rainfall. • Week-1 outlooks call for an increased chance for below-average rainfall over portions of the Gulf of Guinea countries, and parts of southern DRC, northern Angola and northern Zambia. In contrast, there is an increased chance for above-average rainfall over parts of Ethiopia, South Sudan, northeastern DRC, Uganda, Kenya, Rwanda and northern Tanzania.

4. Rainfall Patterns: Last 7 Days During the past seven days, below-average rainfall was observed over portions of Guinea-Conakry, Sierra Leone, parts of northern Cote d’Ivoire and Ghana, Burkina Faso, portions of Nigeria and Gabon, parts of Angola and DRC. In contrast, Liberia, southern Cote d’Ivoire, Cameroon, Congo-Brazzaville, local areas in northern Angola, CAR, much of South Sudan, western and southern Ethiopia, western Kenya, parts of Tanzania, eastern Zambia, and local areas in South Africa and Madagascar.

5. Rainfall Patterns: Last 30 Days During the past 30 days, portions of Senegal and western Mali, Guinea-Bissau, Guinea-Conakry, Sierra Leone, western Liberia, Ghana, portions of Togo and Benin, much of Nigeria, southern Cameroon, Gabon, parts of Chad and DRC, and portions of Angola had below-average rainfall. In contrast, rainfall was above-average over local areas in Mali, much of Cote d’Ivoire, parts of Burkina Faso, northern Benin, parts of Cameroon, Congo-Brazzaville, Central African Republic (CAR), Democratic Republic of Congo (DRC), parts of Sudan, South Sudan, Ethiopia, portions of Uganda, Kenya and northwestern Tanzania, eastern Zambia, southern Botswana, southern Zimbabwe, parts of South Africa and local areas in Madagascar.

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

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

8. Recent Rainfall Evolution Daily evolution of rainfall over the last 90 days at selected locations shows that seasonal total rainfall remained below-average over northern Ghana (bottom left). Parts of Gabon received little or no rainfall over the past 90 days (bottom right). In contrast, seasonal total remained above-average over many parts of South Sudan (top right).

9. Atmospheric Circulation:Last 7 Days Anomalous lower-level cyclonic circulation was observed across southeastern Africa.

10. NCEP GEFS Model ForecastsNon-Bias Corrected Probability of precipitation exceedance Week-1: Valid 17 - 23 Oct, 2017 Week-2: Valid 24 - 30 Oct, 2017 For week-1 (left panel) and week-2 (right panel), there is an increased chance for weekly rainfall totals to exceed 50mm over portions of equatorial Africa.

11. Week-1 Precipitation Outlooks 17 - 23 Oct, 2017 • There is an increased chance for below-average rainfall over parts of Mali, Cote d'Ivoire, Ghana, Togo, Benin, Burkina Faso, Nigeria, Cameroon, Chad, CAR, and South Sudan: A broad area of anomalous lower-level divergence coupled with pockets of anomalous upper-level convergence is expected to suppress rainfall in the region. Confidence: Moderate • There is an increased chance for below-average rainfall over parts of southern DRC, northern Angola and northern Zambia: 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 parts of Ethiopia, South Sudan, Uganda, Kenya, Rwanda and northern Tanzania: Anomalous lower-level convergence is expected to enhance rainfall in the region. Confidence: Moderate

12. Week-2 Precipitation Outlooks 24 – 30 Oct 2017 • There is an increased chance for below-average rainfall over parts of Mali, Guinea, Burkina Faso, Ghana, Togo, Nigeria, Cameroon, Chad, CAR and South Sudan: A broad area of anomalous lower-level divergence coupled with pockets of anomalous upper-level convergence is expected to suppress rainfall in the region. Confidence: Moderate • There is an increased chance for below-average rainfall over southern DRC, northern Angola and Zambia: An area 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 Burundi, Rwanda, Uganda, Kenya, Ethiopia and Somalia: An area 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, below-average rainfall was observed over portions of Guinea-Conakry, Sierra Leone, parts of northern Cote d’Ivoire and Ghana, Burkina Faso, portions of Nigeria and Gabon, parts of Angola and DRC. In contrast, Liberia, southern Cote d’Ivoire, Cameroon, Congo-Brazzaville, local areas in northern Angola, CAR, much of South Sudan, western and southern Ethiopia, western Kenya, parts of Tanzania, eastern Zambia, and local areas in South Africa and Madagascar. • During the past 30 days, portions of Senegal and western Mali, Guinea-Bissau, Guinea-Conakry, Sierra Leone, western Liberia, Ghana, portions of Togo and Benin, much of Nigeria, southern Cameroon, Gabon, parts of Chad and DRC, and portions of Angola had below-average rainfall. In contrast, rainfall was above-average over local areas in Mali, much of Cote d’Ivoire, parts of Burkina Faso, northern Benin, parts of Cameroon, Congo-Brazzaville, Central African Republic (CAR), Democratic Republic of Congo (DRC), parts of Sudan, South Sudan, Ethiopia, portions of Uganda, Kenya and northwestern Tanzania, eastern Zambia, southern Botswana, southern Zimbabwe, parts of South Africa and local areas in Madagascar. • During the past 90 days, rainfall was above-average over portions of southern Mauritania, Senegal, Gambia, Guinea-Bissau, Guinea-Conakry, Sierra Leone, parts of Liberia, Mali, much of Cote d’Ivoire and Burkina Faso, many parts of Niger, much of Togo and Benin, parts of Nigeria and Cameroon, Congo-Brazzaville, much of Central African Republic (CAR), parts of southern Chad, western DRC, Sudan, South Sudan Republic, Uganda, many parts of Ethiopia, local areas in northern Tanzania and parts of Kenya, eastern Zambia, parts of Botswana, South Africa and local areas in Madagascar. In contrast, below-average rainfall was observed over parts of western Mali, eastern Guinea, western Liberia, local areas in Coe d’Ivoire, Ghana, parts of Nigeria, local areas in Niger, portions of Chad, southern Cameroon, Equatorial Guinea, Gabon, parts of Angola, portions of DRC, and parts of South Africa and local areas in Madagascar. • Week-1 outlooks call for an increased chance for below-average rainfall over portions of the Gulf of Guinea countries, and parts of southern DRC, northern Angola and northern Zambia. In contrast, there is an increased chance for above-average rainfall over parts of Ethiopia, South Sudan, northeastern DRC, Uganda, Kenya, Rwanda and northern Tanzania.