The African Monsoon Recent Evolution and

Current Status

Include Week-1 and Week-2 Outlooks

Update prepared byClimate Prediction Center / NCEP

02 June 2014For 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

• Moderate to locally heavy rainfall resulted in moisture surpluses over parts of Guinea-Conakry, Sierra Leone, Liberia, southwestern Mali, southern Chad, eastern Cameroon, parts of CAR, southern Sudan, and portions of South Sudan Republic.

• Week-1 outlooks call for an increased chance for above-average rainfall over eastern Guinea-Conakry, southwestern Mali, eastern Sierra Leone, Liberia, western Cote d’Ivoire, western Burkina Faso, eastern Nigeria, northern Cameroon, southern Chad and northern CAR. In contrast, there is an increased chance for below-average rainfall over parts of western Ethiopia.

Rainfall Patterns: Last 7 Days

During the past seven days, above-average rainfall was observed over eastern Senegal, Guinea-Conakry, eastern Sierra Leone, Liberia, southwestern Mali, southern Chad, eastern Cameroon, local areas in Gabon and Congo-Brazzaville, CAR, southern Sudan, local areas in DRC and Ethiopia, and portions of South Sudan. In contrast, Burkina Faso, portions of Cote d’Ivoire and Ghana, Nigeria, Equatorial Guinea, parts of Gabon and Congo-Brazzaville, many parts of DRC, Uganda, portions of Kenya and Ethiopia had below-average rainfall.

Rainfall Patterns: Last 30 Days

During the past 30 days, rainfall was above-average over much of Guinea-Conakry, western Mali, Sierra Leone, Liberia, much of Cote d’Ivoire, local areas in Burkina Faso, Benin, western Nigeria, eastern Cameroon, Gabon, Congo Brazzaville, parts of CAR, northern DRC, South Sudan and the neighboring places of Sudan, western Ethiopia, southern Somalia and costal Tanzania. In contrast, portions of Burkina Faso, Ghana, many parts of Nigeria, local areas in CAR and DRC, Uganda, Rwanda, Burundi, Kenya, southern Ethiopia, and northern Tanzania had below-average rainfall.

Rainfall Patterns: Last 90 Days

During the past 90 days, eastern Guinea Conakry, Liberia, Cote d’Ivoire, local areas in Ghana, Gabon, eastern CAR, South Sudan, western Ethiopia, local areas in Somalia, coastal Tanzania, and local areas in southern DRC received above-average rainfall. In contrast, rainfall was below-average over local areas in Nigeria, portions of DRC, northern Angola, Uganda, Kenya, northern Mozambique, and much of Madagascar.

Rainfall Patterns: Last 180 Days

During the past 180 days, rainfall was above-average over eastern Guinea-Conakry, Sierra Leone, Liberia, Cote d’Ivoire, local areas in Ghana and Nigeria, Gabon, local areas in Congo Brazzaville, eastern CAR, South Sudan, western Ethiopia, portions of Tanzania, southeastern Angola, eastern Namibia, Botswana, northern Zambia, much of Zimbabwe, parts of Mozambique and South Africa, and parts of Madagascar. In contrast, much of DRC, Angola, Uganda, portions of Kenya, Rwanda, Burundi, and eastern Madagascar had below-average rainfall.

Recent Rainfall Evolution

Daily evolution of rainfall over the last 90 days at selected places reflects that moderate to heavy rainfall resulted in accumulated moisture surpluses over parts of Cote d’Ivoire(bottom panel-left), and South Sudan (top panel-right). In contrast, seasonal total rainfall remained below-average over parts of Kenya (bottom panel-right).

Atmospheric Circulation:Last 7 Days

The 850Pa wind anomalies (left panel) featured easterly flow across northern Indian Ocean and the Horn of Africa.

NCEP GEFS Model ForecastsNon-Bias Corrected Probability of

precipitation exceedance Week-1: Valid 03 June – 09 June 2014Week-2: Valid 10 June – 16 June 2014

For week-1 (left panel) and wek-2 (right-panel), there is an increased chance for rainfall to exceed 50 mm over portions of Nigeria, Cameroon, Gabon, northern DRC and western Ethiopia.

Experimental Week-1 Precipitation Outlooks

June 03 – June 09 2014

1. There is an increased chance for above-average rainfall over eastern Guinea-Conakry, southern Mali, eastern Sierra Leone, Liberia, western Cote d’Ivoire and western Burkina Faso: Anomalous lower-level convergence and upper-level divergence is expected to enhance rainfall in the region. Confidence: Moderate

2. There is an increased chance for above-average rainfall over eastern Nigeria, northern Cameroon, southern Chad, and northern CAR: An axis of anomalous lower-level convergence is expected to enhance rainfall in the region. Confidence: Moderate

3. There is an increased chance for below-average rainfall over parts of western Ethiopia: Pockets of anomalous lower-level divergence and reduced tropospheric moisture is expected to suppress rainfall in the region. Confidence: Moderate

Experimental Week-2 Precipitation Outlooks

June 10 – June 16, 2014

1. There is an increased chance for above-average rainfall over southern Niger and northern Nigeria: An axis of anomalous lower-level convergence and upper-level divergence is expected to enhance rainfall in the region. Confidence: Moderate

2. There is an increased chance for above-average rainfall over western Cameroon, Equatorial Guinea, and western Gabon: Anomalous lower-level onshore flow and upper-level divergence is likely to enhance rainfall in the region. Confidence: Moderate

Summary

• During the past seven days, above-average rainfall was observed over eastern Senegal, Guinea-Conakry, eastern Sierra Leone, Liberia, southwestern Mali, southern Chad, eastern Cameroon, local areas in Gabon and Congo-Brazzaville, CAR, southern Sudan, local areas in DRC and Ethiopia, and portions of South Sudan. In contrast, Burkina Faso, portions of Cote d’Ivoire and Ghana, Nigeria, Equatorial Guinea, parts of Gabon and Congo-Brazzaville, many parts of DRC, Uganda, portions of Kenya and Ethiopia had below-average rainfall.

• During the past 30 days, rainfall was above-average over much of Guinea-Conakry, western Mali, Sierra Leone, Liberia, much of Cote d’Ivoire, local areas in Burkina Faso, Benin, western Nigeria, eastern Cameroon, Gabon, Congo Brazzaville, parts of CAR, northern DRC, South Sudan and the neighboring places of Sudan, western Ethiopia, southern Somalia and costal Tanzania. In contrast, portions of Burkina Faso, Ghana, many parts of Nigeria, local areas in CAR and DRC, Uganda, Rwanda, Burundi, Kenya, southern Ethiopia, and northern Tanzania had below-average rainfall.

• During the past 90 days, eastern Guinea Conakry, Liberia, Cote d’Ivoire, local areas in Ghana, Gabon, eastern CAR, South Sudan, western Ethiopia, local areas in Somalia, coastal Tanzania, and local areas in southern DRC received above-average rainfall. In contrast, rainfall was below-average over local areas in Nigeria, portions of DRC, northern Angola, Uganda, Kenya, northern Mozambique, and much of Madagascar.

• Week-1 outlooks call for an increased chance for above-average rainfall over eastern Guinea-Conakry, southwestern Mali, eastern Sierra Leone, Liberia, western Cote d’Ivoire, western Burkina Faso, eastern Nigeria, northern Cameroon, southern Chad and northern CAR. In contrast, there is an increased chance for below-average rainfall over parts of western Ethiopia.