The African Monsoon Recent Evolution and Current Status

1. The African Monsoon Recent Evolution and Current Status Update prepared by Climate Prediction Center / NCEP 29 March 2010 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 • During the past seven days, western Kenya continued to receive beneficial rains. Heavy rains alleviated dry conditions in northwestern Madagascar • Dry conditions sustained moisture deficits over central Mozambique and the area along the boundary between South Africa and Zimbabwe.

4. Rainfall Patterns: Last 7 Days During the past seven days, dry conditions prevailed along the Guinea coast and the northern areas of central Africa resulting in moisture deficits in this region. Rainfall was above average locally in southwest Ethiopia, western Kenya, northern Uganda, northwestern Tanzania, and the northern areas of DRC. Rainfall was also above average over parts of central Angola and over the area along the boundary between Namibia and Botswana. Below average rainfall persisted in central Mozambique. Rainfall eased along the east coast of Madagascar, while the northwest coast registered much needed downpours.

5. Rainfall Patterns: Last 30 Days During the past 30 days, rainfall was above average over much of Madagascar, local areas in northern Mozambique, parts of Zambia, southern Angola and much of central Africa. Rainfall was also above average over parts of the Greater Horn of Africa, including eastern Uganda, Kenya, southern Somalia, and eastern Ethiopia. Rainfall was below average over parts of western Ethiopia, central Tanzania, parts of southern Malawi, central and southern Mozambique, and northeastern South Africa. Rainfall was above average along the western section of the Gulf of Guinea coast an below average locally over southern Nigeria.

6. Rainfall Patterns: Last 90 Days During the past 90 days, rainfall was above average over parts of eastern Africa, most areas in central Africa, and portions of the northern areas of southern Africa. Rainfall was below average locally over central Mozambique and western Madagascar.

7. Rainfall Patterns: Last 180 Days During the past 180 days, rainfall was above average over parts of southern Africa, most areas in central Africa, and portions of the Greater Horn of Africa. Rainfall was below average over western Madagascar and central Mozambique.

8. Recent Rainfall Evolution Daily evolution of precipitation during the last 90 days at selected regions indicates a return of the rains in southwestern Kenya over the last few days (lower panel – left). Continued dry spells sustained moisture deficits at the boundary between Zimbabwe and South Africa (lower panel – right). Rainfall remained below average along the central coast of Mozambique (upper panel – right).

9. Atmospheric Circulation:Last 7 Days The 850 hPa wind anomaly (left panel) reflected easterly wind anomalies over central Indian Ocean. An area of low level convergence is evident over western central Africa. The 200 hPa wind anomaly (right panel) featured an upper level cyclonic circulation centered over the Mozambique Channel.

10. NCEP GEFS Model ForecastsNon-Bias Corrected Probability of precipitation exceedance Week-1: Valid 30 March– 5 April, 2010Week-2: Valid 6 – 12 April, 2010 For week-1, the global ensemble forecast system (GEFS) suggests over a 90% chance for precipitation to exceed 50 mm locally over western Gabon and southern Angola. Same for week2 except for local areas in northwestern Angola.

11. Experimental Week-1 Precipitation Outlooks Week-1 Outlook 30 March – 5 April, 2010 1. There is an increased chance for below average rainfall along coastal Guinea and parts of central Africa: The weak phase of the MJO and the stronger than normal dry northeasterly winds are expected to suppress precipitation in the region. Confidence: Moderate 2. There is an increased chance for above average rainfall along coastal Tanzania and parts of Mozambique and Malawi:The warm equatorial western Indian Ocean and the associated easterly to northeasterly wind anomalies are expected to enhance rainfall in the region. Confidence: Moderate

12. Experimental Week-2 Precipitation Outlooks Week-2 Outlook 6 - 12 April, 2010 No forecast – Climatology suggested.

13. Summary During the past seven days, dry conditions prevailed along the Guinea coast and the northern areas of central Africa resulting in moisture deficits in this region. Rainfall was above average locally in southwest Ethiopia, western Kenya, northern Uganda, northwestern Tanzania, and the northern areas of DRC. Rainfall was also above average over parts of central Angola and over the area along the boundary between Namibia and Botswana. Below average rainfall persisted in central Mozambique. Rainfall eased along the east coast of Madagascar, while the northwest coast registered much needed downpours. During the past 30 days, rainfall was above average over much of Madagascar, local areas in northern Mozambique, parts of Zambia, southern Angola and much of central Africa. Rainfall was also above average over parts of the Greater Horn of Africa, including eastern Uganda, Kenya, southern Somalia, and eastern Ethiopia. Rainfall was below average over parts of western Ethiopia, central Tanzania, parts of southern Malawi, central and southern Mozambique, and northeastern South Africa. Rainfall was above average along the western section of the Gulf of Guinea coast an below average locally over southern Nigeria. During the past 90 days, rainfall was above average over parts of eastern Africa, most areas in central Africa, and portions of the northern areas of southern Africa. Rainfall was below average locally over central Mozambique and western Madagascar. For week-1, there is an increased chance for below average rainfall along coastal Guinea and parts of central Africa. There is an increased chance for above average rainfall along coastal Tanzania and parts of Mozambique.