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 30 March 2015 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 • Portions of the Gulf of Guinea and the Southern Africa countries, and the Lake Victoria region received above-average rainfall. • Week-1 outlooks call for an increased chance for above-average rainfall over eastern Angola, eastern Namibia, western Zambia, Botswana, portions of western Zimbabwe, eastern DRC, Uganda, Rwanda, Burundi, southwestern Kenya, and northern Tanzania. In contrast, there is an increased chance for below-average rainfall over northern Angola and the neighboring places of southwestern DRC, southern Malawi, and northern Mozambique.

4. Rainfall Patterns: Last 7 Days During the past seven days, above-average rainfall was observed over eastern Cote d’Ivoire, Ghana, Benin, portions of Nigeria and Cameroon, local areas in Gabon, eastern DRC, portions of Angola, Namibia, western Botswana, portions of South Africa, the Lake Victoria region, eastern Kenya, and portions of southern Somalia. In contrast, southern Cameroon, eastern Gabon, Congo-Brazzaville, western DRC, eastern CAR, portions of South Sudan Republic and South Sudan, western Kenya, portions of Tanzania, Malawi, eastern Angola, northern Zambia, local areas in eastern Zimbabwe, portions of Mozambique and Madagascar had below-average rainfall.

5. Rainfall Patterns: Last 30 Days During the past 30 days, rainfall was above-average over portions of Cote d’Ivoire and Ghana, central and southeastern Nigeria, local areas in Cameroon, western Gabon, eastern CAR, western South Sudan Republic, western and northern of DRC, coastal Angola, southeastern Tanzania, portions of northern Mozambique, local areas in Botswana and South Africa, and many parts of Madagascar. In contrast, much of Angola, eastern DRC, Rwanda, Burundi, Uganda, southeastern South Sudan Republic, portions of Ethiopia, Kenya and Tanzania, much of Zambia, Malawi, central and southern Mozambique, portions of Botswana and Zimbabwe, local areas in South Africa and Madagascar had below-average rainfall.

6. Rainfall Patterns: Last 90 Days During the past 90 days, rainfall was above-average over local areas in the Gulf of Guinea countries, portions of southern CAR and northern DRC, southern Malawi, northern Mozambique, and Madagascar. In contrast, Equatorial Guinea, much of Gabon, Angola, central and southern DRC, Namibia, Botswana, Zambia, Tanzania, Rwanda, Burundi, Uganda, portions of Ethiopia, Kenya, South Africa and southern Mozambique had below-average rainfall.

7. Rainfall Patterns: Last 180 Days During the past 180 days, rainfall was above-average over parts of Liberia, Cote d’Ivoire, local areas in Nigeria, southern CAR, western Gabon, portions of northern DRC, South Sudan Republic, local areas in Ethiopia, southern Malawi, northern Mozambique, and central and southern Madagascar. In contrast, southern Cameroon, Equatorial Guinea, eastern Gabon, southern Congo-Brazzaville, Angola, southern DRC, Namibia, portions of Botswana, Zambia, and portions of South Africa had below-average rainfall.

8. Recent Rainfall Evolution Daily evolution of rainfall over the last 90 days at selected places reflects early season moisture surpluses over parts of Nigeria (bottom-left panel). Moderate to heavy rainfall helped to offset some of the seasonal rainfall deficits over eastern Tanzania (bottom-right panel). In contrast, rainfall deficits continued to prevail over many parts of Kenya (top-right panel).

9. Atmospheric Circulation:Last 7 Days The 850hpa wind anomalies (left panel) featured lower-level cyclonic circulation across southern Africa, which 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 31 March – 6 April 2015Week-2: Valid 7 April – 13 April 2015 For week-1 (left panel), there is an increased chance for rainfall to exceed 50 mm over many parts of DRC, eastern Angola, Botswana, northern Zambia, and the Lake Victoria region.

11. Week-1 Precipitation Outlooks • There is an increased chance for below-average rainfall over northern Angola and the neighboring places of southwestern DRC: Anomalous lower-level divergence is expected to suppress rainfall in the region. Confidence: Moderate • There is an increased chance for above-average rainfall over eastern Angola, eastern Namibia, western Zambia, Botswana, and portions of western Zimbabwe: Anomalous lower-level cyclonic circulation is expected to enhance rainfall in the region. Confidence: Moderate • There is an increased chance for above-average rainfall over eastern DRC, Uganda, Rwanda, Burundi, southwestern Kenya, and northern Tanzania: Anomalous lower-level wind convergence, 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, and northern Mozambique: Anomalous lower-level divergence coupled with upper-level convergence is expected to suppress rainfall in the region. Confidence: Moderate 31 March – 06 April 2015

12. Week-1 Precipitation Outlooks 07 April – 13 April 2015 • There is an increased chance for above-average rainfall over southern Cameroon, Equatorial Guinea, Gabon, and portions of western Congo: Anomalous lower-level southwesterly 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 northern DRC and southern CAR: Anomalous lower-level dry northerly flow with its associated lower-level divergence is expected to suppress rainfall in the region. Confidence: Moderate • There is an increased chance for above-average rainfall over southern Ethiopia, and portions of northern Kenya and western Somalia: Anomalous lower-level southeasterly flow from the Indian Ocean, with its associated lower-level convergence is expected to enhance rainfall in the region. Confidence: Moderate

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