The African Monsoon Recent Evolution and Current Status Update prepared by Climate Prediction Center / NCEP 4 April 2008 For more information, visit:

Outline Highlights Recent Evolution and Current Conditions NCEP GEFS Forecasts Summary

Highlights Local areas in southern Ethiopia received beneficial rains resulting in a slow but steady recovery of the Belg rains. Southwestern Kenya received sizable rainfall amounts, and beneficial rains fell in Tanzania and Uganda. Light rains continued to sustain moisture deficits in the southern areas of DRC and Congo. Moisture was adequate along the Guinean coast.

Rainfall Patterns: Last 7 Days During the past 7 days, rainfall diminished significantly across much of southern Africa, but was above average over sections of northeastern South Africa, southern Botswana, and portions of Namibia. Rainfall persisted across Tanzania, southwestern Kenya, Uganda, and eastern DRC and extended northwest to coastal Guinea.

Rainfall Patterns: Last 30 Days Over the last 30 days, rainfall was above average over portions of northeastern South Africa, central and western Namibia, northern Tanzania, and southwestern Kenya. Rainfall was below average over Madagascar, the central areas of Africa, and Ethiopia.

Rainfall Patterns: Last 90 Days Over the past 90 days, rainfall was above average over parts of western southern Africa, northern Mozambique, and Tanzania. Rainfall was below average over the northern areas of Zambia and Tanzania, southern DRC, and Ethiopia.

Rainfall Patterns: Last 180 Days Over the past 180 days, rainfall was above average across most areas in southern Africa. Rainfall was below average over portions of the central areas of Africa and the Greater Horn, including Kenya, Uganda, and Ethiopia. Rainfall was also below average over western coastal Guinea.

Recent Rainfall Evolution Slow but steady recovery of the Belg rains in southern Ethiopia (top panel - right); Adequate moisture in southwestern Kenya (bottom panel – right); Frequent dry spells along the Guinean coast over the past three weeks.

Atmospheric Circulation: Last 7 Days Over the past 7 days, low level westerly wind anomalies (left panel) developed over the southern Indian Ocean (IO). A tropical wave indicated with “T” was evident east of Madagascar. Upper level easterly wind anomalies (right panel) extended from Asia to western Africa. L

NCEP GEFS Model Forecasts Non-Bias Corrected Probability of precipitation exceedance – Week-1 Valid Apr, 2008 The precipitation climatology for the verifying period 5-11 April 2008 displayed (left panel). NCEP global ensemble forecast system (GEFS) suggests a high tilt in the odds (90% or above) for precipitation to exceed 25 mm over sections of western Ethiopia and along coastal Tanzania and Gulf of Guinea (central panel). The highest chance for precipitation to exceed 50 mm (right panel) is confined along the eastern Gulf of Guinea coast.

Summary Over the past seven days, rainfall continued to diminish across southern Africa, except for areas in northeastern South Africa, southern Botswana, and portions of Namibia, which received above average rains. Rainfall was below average along the northern coasts of Madagascar, Mozambique, southern DRC, Congo, and eastern Gabon. To the north, in the Greater Horn of Africa, rainfall persisted and was above average over portions of Tanzania, the southwestern areas of Kenya and Ethiopia, northern DRC and portions of western CAR. Rainfall also extended northwest to coastal Guinea and was near average across most areas. The persistence of wet conditions in the southern part of the GHA resulted in above average rainfall in northern Tanzania and southwestern Kenya over the last 30 days. Light rains resulted in moisture deficits over central Ethiopia, while moderate rains sustained moisture surpluses in portions of northeastern South Africa and Namibia. The wet conditions of the last 30 days in northern Mozambique are lingering effects from TC Jokwe. Below average rainfall persisted in northern Angola, the southern areas of DRC and Congo, and eastern Gabon. Moisture was adequate along the Guinean coast, with slightly below average rainfall at isolated locations. Over the last 90 days, rainfall was above average over parts of western southern Africa, northern Mozambique, and Tanzania. Rainfall was below average over the northern areas of Zambia and Tanzania, southern DRC, and Ethiopia. Rainfall was slightly below average over north central Cote d’Ivoire. Season-to-date rainfall in southern Africa, starting from October 2008, has been overall above average. However, the recent dry spells in the northern areas of Zambia and Tanzania, and the southern areas of DRC resulted in below average rainfall in this subregion. For the period 5 March – 11 April 2008, The NCEP global ensemble forecast system (GEFS) suggests 90% or above chance for precipitation to exceed 25 mm over sections of western Ethiopia and along coastal Tanzania and Gulf of Guinea. There is a high chance for precipitation to exceed 50 mm along the eastern Gulf of Guinea coast.