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 5 March 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 over many places in East Africa, and portions of Southern Africa. • Week-1 outlooks call for an increased chance for below-average rainfall over southeastern Gabon, Cong-Brazzaville, western DRC, Angola, southern Malawi, parts of eastern Zimbabwe and Mozambique. In contrast, there is an increased chance for above-average rainfall over parts of eastern DRC, Rwanda, Burundi, southern Uganda, southwestern Kenya, much of Tanzania, and northeastern Zambia.

4. Rainfall Patterns: Last 7 Days During the past seven days, rainfall was above-average over parts Guinea-Conakry, Sierra Leone, Cote d’Ivoire, Cameroon, eastern CAR, western South Sudan, southern Ethiopia, Uganda, parts of DRC, southeastern Angola, much of Zambia, northern Zimbabwe, Malawi, portions of Mozambique, much of Tanzania, Uganda, Kenya, parts of southern Somalia, and northern Madagascar. In contrast, much of Gabon, southern Congo-Brazzaville, parts of DRC, portions of Angola and Namibia, southern Botswana, southern Zimbabwe, parts of South Africa, and local areas in northern Mozambique and southern Madagascar.

5. Rainfall Patterns: Last 30 Days During the past 30 days, Sierra Leone, parts of Liberia, Cote d’Ivoire, western Ghana, Benin, southern Nigeria, southern Cameroon, CAR, northern Congo-Brazzaville, many parts of DRC, portions of Angola, parts of Tanzania, Kenya, parts of Ethiopia and southern Somalia, Zambia, Malawi, Botswana, much of Zimbabwe, local areas in South Africa, parts of Mozambique, and parts of Madagascar had above-average rainfall. In contrast, much of Gabon, southern Congo-Brazzaville, parts of Angola and DRC, eastern Tanzania, Namibia, northeastern Mozambique, and portions of Madagascar had below-average rainfall.

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

7. Rainfall Patterns: Last 180 Days During the past 180 days, rainfall was above-average over local areas in Guinea-Conakry, Cote d’Ivoire, parts of Burkina Faso, southwestern Ghana, northern Benin, local areas in Nigeria, parts of Cameroon, 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, much of Zambia, local areas in South Africa, many parts of Mozambique, much of Zimbabwe, and northern and eastern Madagascar. In contrast, below-average rainfall was observed over the far western West Africa, Ghana, southern Togo, southern Benin, much of Nigeria, central Chad, Gabon, portions of DRC and Angola, eastern Kenya, local areas in Somalia, Namibia, western and southern Botswana, 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 moderate to locally heavy rainfall helped to gradually erode accumulated rainfall deficits over parts of Zimbabwe (bottom left). Moderate to locally heavy rainfall sustained moisture surpluses across southern Ethiopia (top right), and Tanzania (bottom right).

9. Atmospheric Circulation:Last 7 Days At 850-hPa level (left), anomalous lower-level convergence across parts of Southern Africa, and anomalous cross-equatorial flow across parts of East Africa may have contributed to the observed rainfall surpluses in the regions.

10. NCEP GEFS Model ForecastsNon-Bias Corrected Probability of precipitation exceedance Week-1: Valid 6 – 12 Mar, 2018 Week-2: Valid 13 – 19 Mar, 2018 For week-1 (left panel) and week-2 (right panel), there is an increased chance for weekly rainfall totals to exceed 50mm over parts of Angola, eastern DRC, Rwanda, Burundi, Uganda, parts of Kenya and Tanzania, local areas in Ethiopia, and portions of Zambia.

11. Week-1 Precipitation Outlooks 6 – 12 Mar, 2018 • There is an increased chance for below-average rainfall over southeastern Gabon, Cong-Brazzaville, western DRC, and 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 parts of eastern DRC, Rwanda, Burundi, southern Uganda, southwestern Kenya, much of Tanzania, and northeastern Zambia: An area of anomalous lower-level convergence and upper-level divergence, combined with the projected phase of the MJO is expected to enhance rainfall in the region. Confidence: Moderate • There is an increased chance for below-average rainfall over southern Malawi, parts of eastern Zimbabwe and Mozambique: An area of anomalous lower-level anticyclonic flow, coupled with anomalous upper-level convergence is expected to suppress rainfall in the region. Confidence: Moderate

12. Week-2 Precipitation Outlooks 13 – 19 Mar, 2018 • There is an increased chance for below-average rainfall over portions of Cameroon, western CAR, Equatorial Guinea, Gabon, Congo-Brazzaville, northwestern Angola and western DRC: 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 parts of eastern DRC, Rwanda, Burundi, Uganda, parts of South Sudan, southern Ethiopia, western Kenya, and Tanzania: A broad area of anomalous lower-level convergence and upper-level divergence is expected to enhance rainfall in the region. Confidence: Moderate

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