The African Monsoon Recent Evolution and Current Status Include Week-1 and Week-2 Outlooks Update prepared by Climate Prediction Center / NCEP 06 July 2015 For more information, visit:

Outline Highlights Recent Evolution and Current Conditions NCEP GEFS Forecasts Summary

Highlights: Last 7 Days Weekly total rainfall exceeded 100mm across portions of the central Africa countries. Week-1 outlooks call for an increased chance for above-average rainfall over portions of southern Senegal, Guinea-Bissau, Guinea Conakry, southern Mali, Sierra Leone, Liberia, Cote d'Ivoire, western Burkina Faso, and Ghana. In contrast, there is an increased chance for below-average rainfall over southern CAR, northern DRC, much of South Sudan, and western Ethiopia.

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

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

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

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

Recent Rainfall Evolution Daily evolution of rainfall over the last 90 days at selected places reflects that moderate to heavy rainfall sustained moisture surpluses over portions of South Sudan (top right). In contrast, seasonal total rainfall continued to be below-average over parts of southwestern Mali (bottom left) and Nigeria (bottom right).

Atmospheric Circulation: Last 7 Days The 200hpa wind anomalies (right panel) featured westerly flow across the Greater Horn of Africa, reflecting weaker than normal Tropical Easterly Jet (TEJ).

NCEP GEFS Model Forecasts Non-Bias Corrected Probability of precipitation exceedance Week-1: Valid 07 July – 13 July 2015 Week-2: Valid 14 July – 20 July 2015 For week-1 (left panel) and week-2 (right-panel), there is an increased chance for rainfall to exceed 50 mm over southern Senegal, Guinea-Bissau, Guinea-Conakry, Sierra Leone, southern Mali, and western Ethiopia.

Week-1 Precipitation Outlooks 07 – 13 July, There is an increased chance for above-average rainfall over portions of southern Senegal, Guinea-Bissau, Guinea Conakry, southern Mali, Sierra Leone, Liberia, Cote d'Ivoire, western Burkina Faso, and Ghana: Anomalous easterly flow with its associated lower-level convergence is expected to enhance rainfall in the region. Confidence: Moderate 2.There is an increased chance for below-average rainfall over southern CAR, northern DRC, much of South Sudan, and western Ethiopia: An area of lower-level divergence and upper-level convergence is expected to suppress rainfall in the region. Confidence: Moderate

Week-2 Precipitation Outlooks July, There is an increased chance for above-average rainfall over Guinea-Bissau, portions of southern Senegal, Guinea-Conakry, southern Mali, Sierra Leone and western Liberia: An 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 over northern DRC, southern CAR and portions of South Sudan Republic: An area of anomalous lower-level divergence and upper-level convergence is expected to suppress rainfall in the region. Confidence: Moderate

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