The African Monsoon Recent Evolution and Current Status Include Week-1 and Week-2 Outlooks Update prepared by Climate Prediction Center / NCEP 22 June 2015 For more information, visit:

Outline Highlights Recent Evolution and Current Conditions NCEP GEFS Forecasts Summary

Highlights: Last 7 Days Moisture surpluses prevailed across portions of the central Africa region, extending into western Ethiopia. Weekly total rainfall was below-average over many places in the Gulf of Guinea countries. Week-1 outlooks call for an increased chance for above-average rainfall over Guinea-Conakry, Sierra Leone, southern Mali, western Burkina Faso and western Ethiopia. In contrast, there is an increased chance for below-average rainfall over portions of Cote d’Ivoire, Ghana, Togo, Benin, and Nigeria.

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

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

Rainfall Patterns: Last 90 Days During the past 90 days, rainfall was above-average over Guinea-Conakry, Sierra Leone, Liberia, Cote d’Ivoire, southwestern Ghana, southwestern Nigeria, southern Cameroon, Equatorial Guinea, Gabon, northern Congo-Brazzaville, portions of CAR, South Sudan Republic, southern Sudan, many parts of DRC, Uganda, much of Ethiopia, Kenya, southern Somalia, many parts of Tanzania, Zambia, Botswana, Zimbabwe, and local areas in South Africa. In contrast, parts of Senegal, southern Mali, Burkina Faso, northern Ghana, Togo, Benin, Nigeria, portions of Cameroon, southeastern Chad, eastern CAR, western Angola, portions of Namibia and South Africa, parts of Mozambique, Malawi, local areas in southern Tanzania, portions of Ethiopia, northern Kenya 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, southern Nigeria, many parts of CAR, Gabon, Congo-Brazzaville, much of DRC, South Sudan Republic, southern Sudan, Zambia, southern Malawi, much of Mozambique, portions of Botswana, Zimbabwe, and Madagascar. In contrast, Senegal, southwestern Mali, Burkina Faso, northern Ghana, Togo, Benin, northern Nigeria, northern Cameroon, southern Angola, Namibia, portions of Botswana, South Africa, portions of Tanzania, northern Kenya 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 Sierra Leone (bottom left) and northwestern Ethiopia (top right). In contrast, seasonal total rainfall continued to be below-average over parts of Nigeria (bottom right).

Atmospheric Circulation: Last 7 Days The 850hpa wind anomalies (left panel) featured westerly flow across DRC and the neighboring areas of the Lake Victoria region.

NCEP GEFS Model Forecasts Non-Bias Corrected Probability of precipitation exceedance Week-1: Valid 23 June – 29 June 2015 Week-2: Valid 30 June – 06 July 2015 For week-1 (left panel) and week-2 (right-panel), there is an increased chance for rainfall to exceed 50 mm over local areas in Guinea, Nigeria, Cameroon, northern DRC and western Ethiopia.

Week-1 Precipitation Outlooks June There is an increased chance for above-average rainfall over Guinea-Conakry, Sierra Leone, southern Mali, and western Burkina Faso: 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 southern parts of Cote d’Ivoire, Ghana, Togo, Benin, and Nigeria: An area of anomalous upper-level convergence, combined with the projected phase of the MJO is expected to suppress rainfall in the region. Confidence: Moderate 3.There is an increased chance for above-average rainfall over western Ethiopia: An area of anomalous lower-level convergence is expected to enhance rainfall in the region. Confidence: Moderate

Week-2 Precipitation Outlooks 30 June - 6 July There is an increased chance for above-average rainfall over Guinea-Bissau, Guinea Conakry, Sierra Leone and 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 above-average rainfall over western Ethiopia: Anomalous lower level convergence is expected to enhance rainfall in the region. Confidence: Moderate

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