The African Monsoon Recent Evolution and Current Status

1. The African Monsoon Recent Evolution and Current Status Update prepared by Climate Prediction Center / NCEP 22 February 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 western part of the Gulf of Guinea coast, northeastern DRC, much of Uganda, parts of western Kenya, Rwanda, Burundi, northwestern Tanzania, parts of central Angola, parts of southern Zambia, parts of Botswana, Zimbabwe and much of Mozambique. • Rainfall was below normal over much of Madagascar, southern Angola and northern Namibia.

4. Rainfall Patterns: Last 7 Days During the past seven days, rainfall was above average over western part of the Gulf of Guinea coast, northeastern DRC, much of Uganda, parts of western Kenya, Rwanda, Burundi, northwestern Tanzania, parts of central Angola, parts of southern Zambia, parts of Botswana, Zimbabwe and much of Mozambique. Rainfall was below normal over much of Madagascar, southern Angola and northern Namibia.

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

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

7. Rainfall Patterns: Last 180 Days During the past 180 days, rainfall was above average over the western 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 had above average precipitation (lower panel – left). Despite a few episodes of heavy rains, moisture remained suppressed over central Mozambique and eastern Zimbabwe (upper panel – right), while southern Madagascar continues to experience below average rainfall (lower panel – right).

9. Atmospheric Circulation:Last 7 Days The 850 hPa wind anomaly (left panel) reflected a weak anticyclonic circulation around Madagascar and a strong westerly flow over northwest portion of the continent. The 200 hPa wind anomaly (right panel) reflected a cyclonic circulation over southwestern portion of the continent.

10. NCEP GEFS Model ForecastsNon-Bias Corrected Probability of precipitation exceedance Week-1: Valid 23 February - 01 March, 2010Week-2: Valid 02 - 08 March, 2010 For week-1, the global ensemble forecast system (GEFS) suggests over a 90% chance for precipitation to exceed 50 mm over central part of Angola, northern DRC, western Tanzania, much of Zambia, central Mozambique and northern Madagascar. For week-2 there is increased chance for precipitation to exceed 50 mm over parts of southern DRC, Zambia and parts of central and northern Madagascar.

11. Experimental Week-1 Precipitation Outlooks Week-1 Outlook 23 February – 01 March, 2010 • There is an increased chance for above average precipitation over parts of Angola, much of Zambia, Malawi and northern Mozambique. The anomalous lower level cyclonic flow over parts of southern African countries and the stronger than normal East Afican monsoon flow are expected to enhance rainfall in the region. • 2. There is an increased chance for above average precipitation over parts of northern DRC: The lower tropospheric convergence is expected to be stronger then normal and hence results in enhanced rainfall in the region. Confidence: Moderate

12. Experimental Week-2 Precipitation Outlooks Week-2 Outlook 02 – 08 March, 2010 No forecast – Climatology suggested.

13. Summary • During the past seven days, rainfall was above average over western part of the Gulf of Guinea coast, northeastern DRC, much of Uganda, parts of western Kenya, Rwanda, Burundi, northwestern Tanzania, parts of central Angola, parts of southern Zambia, parts of Botswana, Zimbabwe and much of Mozambique. Rainfall was below normal over much of Madagascar, southern Angola and northern Namibia. • During the past 30 days, rainfall was above normal over local areas in central Ethiopia, Ivory Coast, Gabon, parts of DRC, northern Angola, much of Zambia, parts of Botswana, central and northern South Africa Republic and widespread areas in Mozambique. Rainfall was, however, below normal over much Madagascar, southern Angola, northern Namibia and parts of Zimbabwe and parts of Tanzania. • During the past 90 days, rainfall was above average over Gabon, much of DRC, northern Angola, northern Namibia, southern Zambia and parts of northern Madagascar. Rainfall continued to be below average over much of southern Madagascar and central Mozambique. • For week-1, the global ensemble forecast system (GEFS) suggests over a 90% chance for precipitation to exceed 50 mm over central part of Angola, northern DRC, western Tanzania, much of Zambia, central Mozambique and northern Madagascar. For week-2 there is increased chance for precipitation to exceed 50 mm over parts of southern DRC, Zambia and parts of central and northern Madagascar.