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 03 February 2014 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 • Rainfall surpluses exceeded 100mm over parts of Zimbabwe and southern Mozambique. • Above-average rainfall was also observed over parts of DRC, southern CAR, eastern Angola, and much of Botswana, whereas, suppressed rainfall prevailed over much of Tanzania and northern Mozambique. • Week-1 outlooks call for an increased chance for below-average rainfall over much of Angola, parts of western Zambia, southern Zimbabwe, northeastern South Africa, and southern Mozambique. In contrast, there is an increased chance for above-average rainfall over eastern Namibia, Botswana, parts of South Africa, northern Zimbabwe, southern Zambia, southern Malawi and northern Mozambique.

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

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

6. Rainfall Patterns: Last 90 Days During the past 90 days, parts of Liberia, southern Cote d’Ivoire, southern Nigeria, parts Cameroon, western Gabon, local areas in CAR, Ethiopia and Somalia, western Tanzania, southeastern Angola, western Zambia, eastern Namibia, northern Botswana, Zimbabwe, portions of Mozambique, local areas in South Africa, and many parts of Madagascar received above-average rainfall. In contrast, rainfall was below-average over local areas in Gabon, many parts of DRC, Angola, parts of Zambia, Kenya, eastern Tanzania and local areas in South Africa.

7. Rainfall Patterns: Last 180 Days During the past 180 days, rainfall was above-average over local areas in eastern Senegal, much of Guinea, Sierra Leone, portions of Mali, local areas in Liberia and Cote d’Ivoire, southeastern Nigeria, portions of Cameroon, western Niger, western Gabon, northern Congo Brazzaville, western CAR, Southern Chad, parts of Ethiopia, local areas in Somalia, northwestern Tanzania, southeastern Angola, western Zambia, local areas in Mozambique and South Africa, and much of Madagascar. In contrast, parts of Ghana, Nigeria, eastern Gabon, many parts of DRC, Angola, local areas in Zambia, western Ethiopia, Kenya, southern Somalia and eastern Tanzania had below-average rainfall.

8. Recent Rainfall Evolution Daily evolution of rainfall over the last 90 days at selected places reflects that seasonal total rainfall remained below-average over parts of Angola (bottom panel-left) and Tanzania (top panel-right). In contrast, moderate to heavy rainfall sustained moisture surpluses over parts of Zimbabwe (bottom panel-right).

9. Atmospheric Circulation:Last 7 Days The 850hPa wind anomaly (left panel) featured convergence between northwesterly and southwesterly winds near the Lake Chad region. Anomalous lower level cyclonic flow over southern Africa may have contributed to the observed heavy rainfall in the region.

10. NCEP GEFS Model ForecastsNon-Bias Corrected Probability of precipitation exceedance Week-1: Valid 04 – 10 February 2014Week-2: Valid 11 – 17 February 2014 For week-1 (left panel), there is an increased chance for rainfall to exceed 50 mm over eastern Angola, many parts of Botswana and Zimbabwe, parts of Zambia, Malawi, northern Mozambique, the Comoros Islands, and northern Madagascar. Probabilities of exceedance tend to decrease over much of these areas during week-2 (right panel).

11. Experimental Week-1 Precipitation Outlooks Feb 04 – Feb 10, 2014 • There is an increased chance for below-average rainfall over eastern Angola, and parts of western Zambia: Anomalous lower-level anti-cyclonic flow, with its associated divergence is expected to suppress rainfall in the region. Confidence: Moderate • There is an increased chance for above-average rainfall over eastern Namibia, Botswana, parts of South Africa, northern Zimbabwe, southern Zambia, southern Malawi and northern Mozambique: combination of broad anomalous circulation, anomalous 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 southern Zimbabwe, northeastern South Africa and southern Mozambique: Anomalous lower-level anti-cyclonic flow is expected to suppress rainfall in the region. Confidence: Moderate

12. Experimental Week-2 Precipitation Outlooks Feb 12 – Feb 17, 2014 • There is an increased chance for below-average rainfall over much of Angola northern Namibia, northern Botswana and western Zambia: Anomalous lower-level anti-cyclonic flow with its associated divergence is expected to suppress rainfall in the region. Confidence: Moderate • There is an increased chance for above-average rainfall over eastern Zambia, southern Tanzania, Malawi, northern Mozambique, the Comoros Islands and northern Madagascar: Combination 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 local areas in Cote d’Ivoire and Togo, southern CAR, parts of DRC, local areas in Gabon, Congo Brazzaville and Angola, eastern Namibia, much of Botswana and Zimbabwe, southern Mozambique, local areas in Malawi, South Africa, and Madagascar. In contrast, southern DRC, eastern Angola,, northwestern Namibia, Uganda, much of Tanzania, parts of Zambia, northern Mozambique, and western Madagascar had below-average rainfall. During the past 30 days, rainfall was above-average over local areas in the Gulf of Guinea region, western Gabon, portions of Angola, many parts of DRC, portions of Zambia, central and southern Tanzania, eastern Namibia, parts of Botswana, much of Zimbabwe, local areas in South Africa, southern and northern Mozambique, Malawi, and many parts of Madagascar. In contrast, eastern Gabon, southern Congo Brazzaville, many parts of Angola, local areas in DRC, Rwanda, Burundi, Uganda, southwestern Ethiopia, Kenya, portions of Tanzania, parts of Namibia, South Africa, and northeastern Madagascar received below-average rainfall. During the past 90 days, parts of Liberia, southern Cote d’Ivoire, southern Nigeria, parts Cameroon, western Gabon, local areas in CAR, Ethiopia and Somalia, western Tanzania, southeastern Angola, western Zambia, eastern Namibia, northern Botswana, Zimbabwe, portions of Mozambique, local areas in South Africa, and many parts of Madagascar received above-average rainfall. In contrast, rainfall was below-average over local areas in Gabon, many parts of DRC, Angola, parts of Zambia, Kenya, eastern Tanzania and local areas in South Africa. Week-1 outlooks call for an increased chance for below-average rainfall over much of Angola, parts of western Zambia, southern Zimbabwe, northeastern South Africa, and southern Mozambique. In contrast, there is an increased chance for above-average rainfall over eastern Namibia, Botswana, parts of South Africa, northern Zimbabwe, southern Zambia, southern Malawi and northern Mozambique.