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 December 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 • During the past 7 days, above normal rainfall was realized in western Zambia, eastern Angola and northeastern Namibia. • During the last seven days, parts of the Greater Horn of Africa recorded below normal rainfall.

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, parts of western and southern Ethiopia, eastern 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 During the past 90 days, rainfall was above average in few pockets of west Africa including eastern Senegal, Liberia, parts of Ghana, Benin and western Nigeria, northern DRC, southern Sudan, southwestern Ethiopia, western Kenya and northwestern Tanzania. Rainfall was also above average in southern Zambia, southeastern Angola and Madagascar. Below average rainfall was realized in northeastern Nigeria, Cameroon, Gabon, northwestern Angola, central Mozambique, eastern Kenya and southern Somalia. Rainfall was also below normal in parts of southeastern South Africa Republic.

6. Rainfall Patterns: Last 30 Days During the last 30 days, rainfall was above average southern Ethiopia, few areas of western Kenya, northwestern DRC, eastern Angola, Zambia, northeastern Namibia, northern Botswana, Madagascar and southern Mozambique. Rainfall was below average in most parts of west Africa including Guinea, Ghana, Nigeria, Cameroon, eastern Kenya, Southern Somalia and central Mozambique.

7. Rainfall Patterns: Last 7 Days During the last 7 days, western Zambia, eastern Angola and northeastern Namibia and Madagascar recorded above normal rainfall. Areas that recorded below average rainfall are Kenya, Uganda and southern Somalia in the Greater Horn of Africa. Rainfall was also below average in northeastern DRC, Botswana, Malawi and parts of Mozambique.

8. Recent Rainfall Evolution During the last 30 days, cumulative rainfall was below average (bottom left panel) over gulf of Guinea countries Cameroon, Gabon, Nigeria, and parts of CAR. Rainfall was below normal in the Greater Horn of Africa countries Ethiopia, Uganda and southern Sudan (top right panel). There was a significant Improvement in rainfall over the large area consisting of Southern Zambia, eastern Angola and northeastern Namibia (bottom right panel).

9. Atmospheric Circulation:Last 7 Days Over the past 7 days, the 850 hPa wind anomaly (left panel) featured westerlies in western Indian and an cyclonic feature over northwestern Africa (Left panel). 200hPa circulation anomaly featured sub-tropical westerlies in the southern hemisphere undergoing a 180degree turn to become easterlies entering southern Africa in the upper levels (Left panel).

10. NCEP GEFS Model ForecastsNon-Bias Corrected Probability of precipitation exceedance Week-1: Valid 02 December – 08 December, 2008Week-2: Valid 09 - 15 December, 2008 For week-1, the global ensemble forecast system (GEFS) suggests 90% chance for precipitation to exceed 50 mm over Gabon, Congo, southern DRC, northwest Angola, northern Mozambique and eastern parts of South Africa Republic. For week-2, there is a high chance for precipitation to exceed 50 mm over parts of Angola, Zambia, Malawi, northern Mozambique and Madagascar. 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 02 – 08 December, 2008 In the absence of a clear MJO signal over Africa and weak moisture convergence in the region, Climatology is expected over Central, Southern and Eastern. Africa. Confidence: Moderate. Week-2 Outlook Valid 09-15 December, 2008 Due to conflicting large and local scale signals and in the absence of a clear MJO signal, Climatology is expected over Central, Southern and Eastern Africa.

12. Summary • During the last 7 days, western Zambia, eastern Angola and northeastern Namibia and Madagascar recorded above normal rainfall. Areas that recorded below average rainfall are Kenya, Uganda and southern Somalia in the Greater Horn of Africa. Rainfall was also below average in northeastern DRC, Botswana, Malawi and parts of Mozambique. • During the last 30 days, rainfall was above average southern Ethiopia, few areas of western Kenya, northwestern DRC, eastern Angola, Zambia, northeastern Namibia, northern Botswana, Madagascar and southern Mozambique. Rainfall was below average in most parts of West Africa including Guinea, Ghana, Nigeria, Cameroon, eastern Kenya, Southern Somalia and central Mozambique. • In the absence of a clear MJO signal over Africa and weak moisture convergence in the region, Climatology is expected over Central, Southern and Eastern Africa during week ending 8th December 2008. Climatology is also expected during the week ending 15th December 2008. This is due to conflicting large and local scale signals and in the absence of a clear MJO signal, Climatology is expected over Central, Southern and Eastern Africa.