The African Monsoon Recent Evolution and Current Status

The African Monsoon Recent Evolution and Current Status Include Week-1 and Week-2 Outlooks Update prepared by Climate Prediction Center / NCEP 27 January 2014 For more information, visit: http: //www. cpc. ncep. noaa. gov/products/Global_Monsoons/African_Monsoons/precip_monitoring. shtml

Outline • Highlights • Recent Evolution and Current Conditions • NCEP GEFS Forecasts • Summary

Highlights: Last 7 Days • Below-average rainfall continued to prevail over much of Botswana, Namibia, southern Zimbabwe, and portions of South Africa, whereas, northern half of the Southern Africa countries, and Madagascar received above-average rainfall. • Week-1 outlooks call for an increased chance for above-average rainfall over eastern Namibia, southeastern Angola, southern Zambia, Botswana, Zimbabwe, South Africa, and Lesotho. In contrast, there is an increased chance for below-average rainfall over much of Angola.

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

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

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

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, northern Mozambique, and Madagascar. In contrast, local areas in northern Cote d’Ivoire, much of Ghana, Togo, Benin, Nigeria, eastern Gabon, many parts of DRC, parts of Angola, local areas in Zambia, western Ethiopia had below-average rainfall.

Recent Rainfall Evolution Daily evolution of rainfall over the last 90 days at selected places reflects that moderate rains helped to erode accumulated rainfall deficits over southern Angola(bottom panel-left) and central Tanzania (top panel-right). Very heavy rainfall sustained moisture surpluses over Madagascar (bottom panel-right).

Atmospheric Circulation: Last 7 Days The 850 h. Pa wind anomaly (left panel) featured moist southeasterly flow near the Gulf of Guinea coast. Strong upper level anti-cyclonic anomaly was observed over the eastern Mediterranean Sea and the neighboring areas of North Africa and southern Europe (right panel).

NCEP GEFS Model Forecasts Non-Bias Corrected Probability of precipitation exceedance Week-1: Valid 28 January – 03 February 2014 Week-2: Valid 04 – 10 February 2014 For week-1 (left panel), there is an increased chance for rainfall to exceed 50 mm over parts of Angola, Zambia, Malawi, central Mozambique, Zimbabwe, Namibia, parts of Botswana, South Africa and Madagascar. Probabilities of exceedance tend to decrease during week-2 (right panel).

Experimental Week-1 Precipitation Outlooks Jan 28 – Feb 03, 2014 1. There is an increased chance for below-average rainfall over much of Angola: Anomalous lower-level divergence is expected to suppress rainfall in the region. Confidence: Moderate 2. There is an increased chance for above-average rainfall over eastern Namibia, southeastern Angola, southern Zambia, Botswana, Zimbabwe, South Africa, and Lesotho: Anomalous lower-level cyclonic circulation, with its associated convergence is expected to enhance rainfall in the region. Confidence: Moderate

Experimental Week-2 Precipitation Outlooks Feb 4 – Feb 10, 2014 1. There is an increased chance for below-average rainfall over much of Angola and parts of DRC: Anomalous lower-level divergence is expected to suppress rainfall in the region. Confidence: Moderate 2. There is an increased chance for above-average rainfall over eastern Namibia, Botswana, western South Africa, and Zimbabwe: Interaction between midlatitude and tropical systems across Southern Africa is expected to enhance rainfall in the region. Confidence: Moderate

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