The African Monsoon Recent Evolution and Current Status

1. The African Monsoon Recent Evolution and Current Status Update prepared by Climate Prediction Center / NCEP 01 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, rainfall was above average over the southern part of the Ivory Coast and Ghana, parts of DRC, much of Uganda and the surrounding region, much of central Mozambique, much of Zambia, parts of southern and eastern Angola, northern Zimbabwe, parts of Botswana, and southern part of the South Africa Republic. • Rainfall was below average over much of Madagascar, northern parts of the South Africa Republic, parts of Namibia, northern Angola, southern Gabon and southern Congo.

4. Rainfall Patterns: Last 7 Days During the past seven days, rainfall was above average over the southern part of the Ivory Coast and Ghana, parts of DRC, much of Uganda and the surrounding region, much of central Mozambique, much of Zambia, parts of southern and eastern Angola, northern Zimbabwe, parts of Botswana, and southern part of the South Africa Republic. Rainfall was below average over much of Madagascar, northern parts of the South Africa Republic, parts of Namibia, northern Angola, southern Gabon and southern Congo.

5. Rainfall Patterns: Last 30 Days During the past 30 days, rainfall was above normal over local areas in central Ethiopia, Ivory Coast, much of the DRC, Uganda and the adjacent region, parts of Angola, much of Zambia and Mozambique, parts of Botswana, parts of South Africa Republic. Rainfall was, however, below average over much Madagascar, southern Congo, northern and southeastern parts of Angola, much of Namibia, parts of Zimbabwe, northern parts of the South Africa Republic and parts of Tanzania.

6. Rainfall Patterns: Last 90 Days During the past 90 days, rainfall was above average over Gabon, much of the DRC, northern Angola, parts of northern Namibia, southern Zambia and local areas of northern Madagascar. Rainfall continued to be below average over much of central and southern Madagascar and parts of central Mozambique.

7. Rainfall Patterns: Last 180 Days During the past 180 days, rainfall was above average over the western parts of the Sahel and below average along coastal Guinea. Rainfall was also below average along the boundary between Sudan and Ethiopia, and over southern Uganda. Rainfall was above average over much of central Africa, while it is below average over central Mozambique, central and southern Madagascar.

8. Recent Rainfall Evolution Daily evolution of precipitation during the last 90 days at selected regions shows that the region in and around Gabon, in spite of last week’s dry spell, had above average precipitation (lower panel – left). Due to last 20 days of heavy rains, moisture deficits have been reduced significantly over much of Mozambique including central the parts (upper panel – right), while southern and central Madagascar continue to experience below average rainfall (lower panel – right).

9. Atmospheric Circulation:Last 7 Days The 850 hPa wind anomaly (left panel) reflected a weak cyclonic circulation over Angola and an anticyclonic circulation over Madagascar and a southerly cross-Equatorial flow along the Tanzania coast into Kenya and Somalia. The 200 hPa wind anomaly (right panel) reflected a cyclonic circulation over southern portion of the continent as well as one centered over south of Madagascar.

10. NCEP GEFS Model ForecastsNon-Bias Corrected Probability of precipitation exceedance Week-1: Valid 02 - 08 March, 2010Week-2: Valid 09 - 15 March, 2010 For week-1, the global ensemble forecast system (GEFS) suggests over a 90% chance for precipitation to exceed 50 mm over central parts of Angola, southern DRC, northern Mozambique and northern Madagascar. For week-2 there is increased chance for precipitation to exceed 50 mm over central Angola, Gabon, southern Cameroon and to a lesser extent northern parts of Madagascar.

11. Experimental Week-1 Precipitation Outlooks Week-1 Outlook 02 – 08 March, 2010 1. There is an increased chance for above average precipitation over parts of the Horn of Africa, Eastern and southern DRC, parts of Angola, Zambia, Malawi and northern Mozambique. Interactions between mid-latitude and tropical systems across the Horn of Africa, stronger than normal easterlies from the Indian Ocean across East Africa and anomalous cyclonic flow over parts of southern Africa countries are expected to increase rainfall in the regions. . 2. There is an increased chance for above average rainfall over much of Madagascar: Anomalous easterlies from the Indian Ocean and their associated convergence are expected to enhance rainfall in the region.. Confidence: Moderate

12. Experimental Week-2 Precipitation Outlooks Week-2 Outlook 09 – 15 March, 2010 No forecast – Climatology suggested.

13. Summary • During the past seven days, rainfall was above average over the southern part of the Ivory Coast and Ghana, parts of DRC, much of Uganda and the surrounding region, much of central Mozambique, much of Zambia, parts of southern and eastern Angola, northern Zimbabwe, parts of Botswana, and southern part of the South Africa Republic. Rainfall was below average over much of Madagascar, northern parts of the South Africa Republic, parts of Namibia, northern Angola, southern Gabon and southern Congo. • During the past 30 days, rainfall was above normal over local areas in central Ethiopia, Ivory Coast, much of the DRC, Uganda and the adjacent region, parts of Angola, much of Zambia and Mozambique, parts of Botswana, parts of South Africa Republic. Rainfall was, however, below average over much Madagascar, southern Congo, northern and southeastern parts of Angola, much of Namibia, parts of Zimbabwe, northern parts of the South Africa Republic and parts of Tanzania. • During the past 90 days, rainfall was above average over Gabon, much of the DRC, northern Angola, parts of northern Namibia, southern Zambia and local areas of northern Madagascar. Rainfall continued to be below average over much of central and southern Madagascar and parts of central Mozambique. • For week-1, the global ensemble forecast system (GEFS) suggests over a 90% chance for precipitation to exceed 50 mm over central parts of Angola, southern DRC, northern Mozambique and northern Madagascar. For week-2 there is increased chance for precipitation to exceed 50 mm over central Angola, Gabon, southern Cameroon and to a lesser extent northern parts of Madagascar.