The African Monsoon Recent Evolution and Current Status

1. The African Monsoon Recent Evolution and Current Status Update prepared by Climate Prediction Center / NCEP 24 November 2008 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 • Experimental Week-1 and Week-2 Outlooks • Summary

3. Highlights:Last 7 Days • Over the last 7 days, rainfall was below average in northeastern DRC, Uganda, Kenya, southern Somalia, southwestern Gabon and southern Mozambique. Above average rainfall was recorded in northeastern Madagascar, southern Zambia, northern Botswana, and northwestern DRC. • An increased chance for above average rainfall over parts of Congo Basin, Angola, Zambia, western Tanzania, Zimbabwe, central and northwestern Mozambique.

4. Rainfall Patterns: Last 180 Days Over the past 180 days, rainfall was above average over northern Madagascar, parts of Zambia, western Sahel, Central Africa Republic, northern DRC, southern Sudan, central Ethiopia, Uganda and western Kenya. Rainfall was below average in southern DRC, parts of Cameroon, Gabon, northeastern Nigeria, Eritrea, central Sudan and northern Ethiopia.

5. Rainfall Patterns: Last 90 Days Over the past 90 days, rainfall was above average in few areas of west Africa including Guinea, Liberia, parts of Ghana and western Nigeria. Above average rainfall was also recorded in the DRC, western Zambia and northern Madagascar. In the Greater Horn of Africa, rainfall was above average in southern Sudan, central Ethiopia, and in Uganda and western Kenya. Rainfall was below average in southern DRC. Rainfall was also below normal in parts of southeastern South Africa Republic.

6. Rainfall Patterns: Last 30 Days Over the last 30 days, rainfall was below average in parts of Guinea, southern Nigeria, parts of Cameroon, CAR, southern Sudan, and parts of Gabon, eastern Kenya and southern Somalia. Rainfall was above normal central Ethiopia, northern Somalia, western Kenya, parts of DRC, eastern Angola and southern Zambia, northeastern part of South Africa Republic and Madagascar. Central Mozambique recorded below average rainfall.

7. Rainfall Patterns: Last 7 Days Over the last 7 days, rainfall was below average in northeastern DRC, Uganda, Kenya, southern Somalia, southwestern Gabon and southern Mozambique. Above average rainfall was recorded in northeastern Madagascar, southern Zambia, northern Botswana, and northwestern DRC.

8. Recent Rainfall Evolution Over the last 30 days, cumulative rainfall was below average (bottom left panel) over southern Cameroon, Gabon, southeastern Nigeria and parts of CAR. Rainfall was above normal in central Ethiopia, Uganda and western Kenya (top right panel). Improved rainfall conditions have resulted in above average rainfall in southern Zambia, eastern Botswana and northern parts of South Africa Republic (bottom right panel).

9. Atmospheric Circulation:Last 7 Days Over the past 7 days, the 850 hPa wind anomaly (left panel) featured northerlies in Arabian sea recurving to become westerlies in equatorial parts of western Indian Ocean off east Africa and there was a weak anticyclonic circulation over the Sahara (Left panel). 200hPa circulation featured two anticyclonic circulations centered over the Mozambique channel and southeastern Atlantic off the coast of Angola.

10. NCEP GEFS Model ForecastsNon-Bias Corrected Probability of precipitation exceedance Week-1: Valid 25 November – 01 December, 2008Week-2: Valid 02 - 08 December, 2008 For week-1, the global ensemble forecast system (GEFS) suggests 90% chance for precipitation to exceed 50 mm over the southern DRC, eastern Angola, Zambia, western Tanzania, northern Mozambique, southeastern parts of South Africa and Madagascar. For week-2, there is a high chance for precipitation to exceed 50 mm over southern parts of the DRC, Zambia and eastern parts of South Africa. Note: The GFS tends to suppress (increase) precipitation in the Sahel (Gulf of Guinea region).

11. Experimental Week-1 & Week-2 Precipitation Outlooks Week-1 Outlook Valid 25 November – 01 December, 2008 An increased chance for above average rainfall over parts of Congo Basin, Angola, Zambia, western Tanzania, Zimbabwe, central and northwestern Mozambique. Northeasterly wind from the northeastern DRC, and a favorable westerly moist wind from the Atlantic Ocean are expected to enhance the precipitation in the region. Confidence: Moderate. Week-2 Outlook Valid 02-08 December, 2008 Due to conflicting large and local scale signals and in the absence Of organized MJO, climatology is expected.

12. Summary • Over the last 7 days, rainfall was below average in northeastern DRC, Uganda, Kenya, southern Somalia, southwestern Gabon and southern Mozambique. Above average rainfall was recorded in northeastern Madagascar, southern Zambia, northern Botswana, and northwestern DRC. • Over the last 30 days, rainfall was below average in parts of Guinea, southern Nigeria, parts of Cameroon, CAR, southern Sudan, and parts of Gabon, eastern Kenya and southern Somalia. Rainfall was above normal central Ethiopia, northern Somalia, western Kenya, parts of DRC, eastern Angola and southern Zambia, northeastern part of South Africa Republic and Madagascar. Central Mozambique recorded below average rainfall. • An increased chance for above average rainfall over parts of Congo Basin, Angola, Zambia, western Tanzania, Zimbabwe, central and northwestern Mozambique. Northeasterly wind from the northeastern DRC, and a favorable westerly moist wind from the Atlantic Ocean are expected to enhance the precipitation in the region.