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 23 January 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 • Weekly total rainfall exceeded 100mm across southeastern Angola, western Zambia, and parts of Zimbabwe and Mozambique. • Week-1 outlooks call for an increased chance for above-average rainfall over southwestern Angola, much of Botswana, portions of western Zambia and northern South Africa. In contrast, there is an increased chance for below-average rainfall over portions of Angola and Madagascar.

4. Rainfall Patterns: Last 7 Days During the past seven days, rainfall was above-average over local areas in DRC, southeastern Angola, western and central Zambia, portions of Mozambique and local areas in Madagascar. In contrast, parts of Gabon and southern Congo-Brazzaville, central and northern Angola, local areas in DRC, Uganda, much of Tanzania, eastern Zambia, Namibia, Botswana, portions of South Africa, Malawi, local areas in Mozambique and much of Madagascar had below-average rainfall.

5. Rainfall Patterns: Last 30 Days During the past 30 days, rainfall was above-average over Equatorial Guinea, western Gabon, southern Congo-Brazzaville, portions of northern DRC, southeastern Angola, eastern Namibia, much of Zambia, Botswana, much of South Africa, Lesotho, Swaziland, Zimbabwe, central and southern Mozambique, and southern Malawi. In contrast, eastern Gabon, central and northern Congo, many parts of DRC and Angola, portions of Namibia, Uganda, southwestern Ethiopia, Kenya, Tanzania, northern Mozambique and much of Madagascar had below-average rainfall.

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

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

8. Recent Rainfall Evolution Daily evolution of rainfall over the last 90 days at selected locations shows moderate to heavy rainfall sustained moisture surpluses across southern Mozambique (bottom left). In contrast, seasonal total rainfall remained below-average across portions of Tanzania (top right) and Madagascar (bottom right).

9. Atmospheric Circulation:Last 7 Days An area of anomalous lower-level convergence (left panel) and upper-level divergence (right panel) across southeastern 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 24 – 30 Jan, 2017 Week-2: Valid 31 Jan – 6 Feb, 2017 For week-1 (left panel) and week-2 (right panel), there is an increased chance for weekly rainfall totals to exceed 50mm over local areas in Angola and Namibia, much of Zambia, Botswana, Zimbabwe, northeastern South Africa, Malawi, northern Mozambique, and portions of Madagascar.

11. Week-1 Precipitation Outlooks 24 – 30 January, 2017 • There is an increased chance for above-average rainfall over southwestern Angola: Anomalous westerly flow from the Atlantic Ocean with its associated lower-level convergence is expected to enhance rainfall in the region. Confidence: Moderate • There is an increased chance for below-average rainfall over portions of Angola: An area of 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 much of Botswana, portions of western Zambia, and northern South Africa: An area of 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 Madagascar: An area of anomalous lower-level anticyclonic circulation and upper-level convergence is expected to suppress rainfall in the region. Confidence: Moderate

12. Week-2 Precipitation Outlooks 31 Jan – 6 Feb, 2017 • There is an increased chance for below-average rainfall over western and central Angola: An area of 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 eastern Namibia and western Botswana: An area of anomalous lower-level cyclonic circulation 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 and southern Mozambique: An area of anomalous lower-level divergence and upper-level convergence is expected to suppress rainfall in the region. Confidence: Moderate

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