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 12 February 2018 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 • Above-average rainfall was observed across eastern Angola, much of Zambia, northern Botswana, northern Zimbabwe, Malawi, Mozambique and southern Madagascar. • Week-1 outlooks call for an increased chance for above-average rainfall over parts of Gabon, Congo-Brazzaville, western DRC, northwestern Angola, portions of western Zambia, Zimbabwe, and Mozambique. In contrast, there is an increased chance for below-average rainfall over southern Angola, northwestern Namibia, portions of Burundi, eastern DRC, Tanzania, eastern Zambia, northern Malawi, and northern Mozambique.

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

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

6. Rainfall Patterns: Last 90 Days During the past 90 days, rainfall was below-average over much of Liberia, parts of Cote d’Ivoire, Gabon, portions of Angola and DRC, southern Zambia, Namibia, much of Botswana and Zimbabwe, many parts of South Africa, southern Mozambique, southern Malawi, parts of South Sudan Republic, southern Ethiopia, Uganda, Kenya, and southwestern Madagascar. In contrast, above-average rainfall was observed over parts of southern Cameroon, much of Congo-Brazzaville, CAR, portions of DRC and Angola, many parts of Tanzania, portions of Zambia, northern and central Mozambique, parts of South Africa, and northern and eastern Madagascar.

7. Rainfall Patterns: Last 180 Days During the past 180 days, rainfall was above-average over parts of Senegal, portions of Mali, parts of Guinea-Conakry, Sierra Leone, Cote d’Ivoire, Burkina Faso, southwestern Ghana, parts of Niger, northern Togo, northern Benin, local areas in Cameroon and Chad, Central African Republic (CAR), Sudan, South Sudan, Ethiopia, parts of Somalia, portions of Kenya, much of Tanzania, Rwanda, Burundi, local areas in Uganda, much of Congo-Brazzaville, portions of Democratic Republic of Congo (DRC), parts of Angola, portions of Zambia, local areas in South Africa, central and northern Mozambique, and northern and eastern Madagascar. In contrast, below-average rainfall was observed over parts of Mauritania, western Mali, parts of Guinea, Liberia, Ghana, portions of Nigeria, central Chad, Gabon, portions of DRC and Angola, eastern Kenya, local areas in Somalia, Namibia, much of Botswana and Zimbabwe, southern Zambia, western and southern Mozambique, much of South Africa and southwestern 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 much of southern Zambia (bottom left) and parts of Zimbabwe (bottom right), despite increase in rainfall over the past two weeks. In contrast, the 90-day total rainfall remained above-average over northern Mozambique(top right).

9. Atmospheric Circulation:Last 7 Days At 850-hPa level (left), anomalous lower-level easterly winds prevailed across the northern parts of Southern Africa.

10. NCEP GEFS Model ForecastsNon-Bias Corrected Probability of precipitation exceedance Week-1: Valid 13 – 19 Feb, 2018 Week-2: Valid 20 – 26 Feb, 2018 For week-1 (left panel), there is an increased chance for weekly rainfall totals to exceed 50mm over much of Gabon, parts of Angola, local areas in DRC, western Zambia, Zimbabwe, central Mozambique, and much of Madagascar. For week-2 (right panel), there is an increased chance for weekly rainfall totals to exceed 50mm over southwestern Gabon, much of Angola, and local areas in Ethiopia, DRC, Zambia, Zimbabwe, South Africa, and much of Madagascar.

11. Week-1 Precipitation Outlooks 13 – 19 Feb, 2018 • There is an increased chance for above-average rainfall over parts of Gabon, Congo, western DRC, and northwestern Angola: 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 parts of southern Angola and Namibia: An area of anomalous lower-level divergence coupled with an anomalous upper-level cyclonic circulation is expected to suppress rainfall in the region. Confidence: Moderate. • There is an increased chance for above-average rainfall over western DRC, portions of western Zambia, Zimbabwe, and Mozambique: 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 portions of Burundi, eastern DRC, Tanzania, eastern Zambia, northern Malawi, and northern Mozambique: An area of anomalously strong lower-level divergence and upper-level convergence is expected to suppress rainfall in the region. Confidence: Moderate.

12. Week-2 Precipitation Outlooks 20 – 26 Feb, 2018 • There is an increased chance for above-average rainfall over portions of Gabon, Congo, western DRC, Angola, northern Namibia, and western Zambia: A broad region of anomalous lower-level convergence coupled and upper-level divergence is expected to enhance rainfall in the region. Confidence: Moderate • There is an increased chance for below-average rainfall over parts of eastern Zambia, northern Malawi, Tanzania, and northern Mozambique: An area of anomalous lower-level divergence coupled with upper-level convergence is expected to suppress rainfall in the region. Confidence: Moderate • There is an increased chance for above-average rainfall over portions of Ethiopia: An area of anomalous lower-level and upper-level divergence is expected to enhance rainfall in the region. Confidence: Moderate • There is an increased chance for above-average rainfall over parts of Madagascar: An area of anomalous upper-level divergence is expected to enhance rainfall in the region. Confidence: Moderate

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