1. The African Monsoon Recent Evolution and Current Status Include Week-1 and Week-2 Outlooks Update prepared by Climate Prediction Center / NCEP 30 September 2013 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 Weekly total rainfall exceeded 120mm over local areas in Liberia and western Cote d’Ivoire, portions of Cameroon, and parts of Central African Republic(CAR). Week-1 outlooks call for an increased chance for below-average rainfall over portions of southern Sudan and the neighboring areas of South Sudan Republic. In contrast, there is an increased chance for above-average rainfall over northern Somalia and the neighboring areas of eastern Ethiopia, southern Malawi, central and northern Mozambique and southern Tanzania.

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

5. Rainfall Patterns: Last 30 Days During the past 30 days, rainfall was below-average over Guinea-Bissau, local areas in Mali and Niger, eastern Liberia, coastal Cote d’Ivoire, parts of Ghana, eastern Burkina Faso, Togo, Benin and much of Nigeria, Equatorial Guinea, Gabon, portions of CAR, southern Sudan, portions of Angola and DRC, western Ethiopia, and Eritrea. In contrast, eastern Senegal, much of Guinea, portions of Burkina Faso and Mali, southeastern Nigeria, much of Cameroon, southern Chad, western CAR, local areas in DRC and Ethiopia, and parts of the Lake Victoria region received above-average rainfall.

6. Rainfall Patterns: Last 90 Days During the past 90 days, eastern Senegal, Guinea, Sierra Leone, portions of Mali, local areas in Burkina Faso, southern Niger, local areas in southern Chad, western CAR and portions of Ethiopia received above-average rainfall. In contrast, rainfall was below- average over many places in Liberia, Cote D’Ivoire, Ghana, Togo, Benin, portions of Nigeria, Equatorial Guinea, northern Gabon, and local areas in Congo, DRC Sudan, and Eritrea.

7. Rainfall Patterns: Last 180 Days During the past 180 days, rainfall was above-average over parts of Senegal, Guinea, Sierra Leone, portions of Mali, Burkina Faso, western Niger, portions of CAR, Southern Chad, portions of DRC and South Sudan, many parts of Ethiopia, western Kenya, and local areas in Somalia. In contrast, parts of Liberia, Ghana, Southern Togo, Benin, Nigeria, southern Cameroon, Equatorial Guinea, northern Gabon, central Congo, local areas in eastern DRC, and local areas in Madagascar had below-average rainfall.

8. Recent Rainfall Evolution Daily evolution of rainfall over the last 90 days at selected places reflects that moderate to heavy rainfall helped to offset accumulated rainfall deficits over parts of Kenya(top panel-right). Seasonal total rainfall remained below-average, despite frequent rainfall observation over portions of Nigeria(bottom panel left). Moderate to heavy rainfall sustained rainfall surpluses over parts of Cameroon (bottom panel-right).

9. Atmospheric Circulation: Last 7 Days The 850hPa wind anomaly (left panel) featured anomalous lower-level westerly winds across the Gulf of Guinea countries, which may have contributed to the observed above- average rainfall in the region. Anomalous dry northerly winds across the Horn of Africa may have contributed to the observed suppressed rainfall in the region. The 200hpa wind anomaly (right panel) featured anomalous upper-level anti-cyclonic circulation over southern Africa.

10. NCEP GEFS Model Forecasts Non-Bias Corrected Probability of precipitation exceedance Week-1: Valid October 1– October 7, 2013 Week-2: Valid October 8– October 14, 2013 For week-1 (left panel) and week-2 (right-panel), there is an increased chance for rainfall to exceed 50 mm over many places in the Central African countries, and portions of Ethiopia.

11. Experimental Week-1 Precipitation Outlooks Oct 1 – Oct 7, 2013 1.There is an increased chance for below-average rainfall over portions of southern Sudan and the neighboring areas of South Sudan Republic: Anomalous lower-level anti-cyclonic turning is expected to suppress rainfall in the region. Confidence: Moderate 2.There is an increased chance for above-average rainfall over northern Somalia and the neighboring areas of eastern Ethiopia: Stronger than normal cross- equatorial flow, with its associated convergence across the Horn of Africa is expected to enhance rainfall in the region. Confidence: Moderate 3.There is an increased chance for above-average rainfall over southern Malawi, central and northern Mozambique, and southern Tanzania: Anomalous southeasterly winds from the Indian Ocean, with their associated convergence over Southeast Africa are likely to enhance rainfall in the region. Confidence: Moderate

12. Experimental Week-2 Precipitation Outlooks Oct 8 – Oct 14, 2013 1.There is an increased chance for below-average rainfall over southern Sudan, the northern part of South Sudan Republic and the neighboring areas of CAR: Anomalous lower-level northerly winds with their associated divergence are expected to suppress rainfall in the region. Confidence: Moderate 2.There is an increased chance for above-average rainfall over southeastern Ethiopia and northern Somalia: Stronger than normal cross-equatorial flow with its associated convergence is likely to enhance rainfall in the region. Confidence: Moderate

13. Summary During the past seven days, above-average rainfall was observed over coastal Guinea, Sierra Leone, Liberia, portions of Cote d’Ivoire and Ghana, Togo, northern Benin, southern Burkina Faso, local areas in Nigeria, much of Cameroon, northern Congo, western CAR, local areas in DRC and Uganda, portions of South Sudan, and local areas in Kenya and Namibia. In contrast, portions of Guinea, local areas in Burkina Faso, parts of Nigeria, much of Equatorial Guinea and Gabon, central and northern Angola, and parts of DRC and Ethiopia. During the past 30 days, rainfall was below-average over Guinea-Bissau, local areas in Mali and Niger, eastern Liberia, coastal Cote d’Ivoire, parts of Ghana, eastern Burkina Faso, Togo, Benin and much of Nigeria, Equatorial Guinea, Gabon, portions of CAR, southern Sudan, portions of Angola and DRC, western Ethiopia, and Eritrea. In contrast, eastern Senegal, much of Guinea, portions of Burkina Faso and Mali, southeastern Nigeria, much of Cameroon, southern Chad, western CAR, local areas in DRC and Ethiopia, and parts of the Lake Victoria region received above-average rainfall. During the past 90 days, eastern Senegal, Guinea, Sierra Leone, portions of Mali, local areas in Burkina Faso, southern Niger, local areas in southern Chad, western CAR and portions of Ethiopia received above-average rainfall. In contrast, rainfall was below-average over many places in Liberia, Cote D’Ivoire, Ghana, Togo, Benin, portions of Nigeria, Equatorial Guinea, northern Gabon, and local areas in Congo, DRC Sudan, and Eritrea. Week-1 outlooks call for an increased chance for below-average rainfall over portions of southern Sudan and the neighboring areas of South Sudan Republic. In contrast, there is an increased chance for above-average rainfall over northern Somalia and the neighboring areas of eastern Ethiopia, southern Malawi, central and northern Mozambique and southern Tanzania.