Early season rainfall deficits in the northern sector of East Africa

• Early season rainfall deficits were observed in eastern Sudan, Afar and eastern Ethiopia; Karamoja, Uganda; and the Turkana District of Kenya.

• Below-average rains and an earlier-than-normal end to the March to May rainy season in Rwanda and Burundi are expected reduce Season B harvests through July.

• Early El Niño-like conditions are likely to result in average to below-average rainfall performance for the June to September main rainy season in the northern sector of East Africa.

Agricultural production deficits are expected in Kenya, Rwanda, Burundi, and Somalia following the generally below-average March to May rainy season in the region. Current crop simulation models for maize and other grains, in addition to field reports in Burundi and Rwanda estimate production deficits of between 30 to 50 percent as a result of erratic rainfall, poor distribution and rainfall deficits between April and May. Areas of concern include central and southern regions of Rwanda, together with southern cropping regions of Burundi. Other cropping zones in both countries are likely to have near-average crop production.

Similarly, below-average crop production is likely in the Rift Valley regions of Kenya. Production deficits of between 10 to 40 percent are expected in the maize producing areas of Uasin Gishu, Trans-Nzoia and Baringo. Deficits are also expected in the eastern and coastal marginal cropping areas of Kenya. However, the key maize producing regions of the northern Rift Valley and western districts of Kenya are like to gradually recover to near-normal cropping conditions with ongoing rains through September.  In south-central Somalia, with the exception of the Bay Region and Lower Shabelle, well below-average production is likely this season as well as delayed harvests in August/September. In the Bay Region and Lower Shabelle, maize and sorghum production will likely be near normal.

Rainfall deficits of 50 to 75 millimeters (mm) were observed during the beginning of the June to September rainy season in eastern Sudan (Figure 1). Similarly, the Afar and eastern regions of Ethiopia, Turkana District of Kenya and the neighboring Karamoja District of Uganda received below-average rainfall in June. Some areas of southern Sudan and western Ethiopia received above-average rainfall last month. Positive rainfall anomalies were also observed in most of Uganda, western Kenya and western South Sudan during June.

The eMODIS Normalized Vegetation Difference Index (NDVI) anomalies shown in Figure 2 indicate drier-than-normal conditions during the third dekad of June in the pastoral zones of northern Tanzania, eastern Rwanda and Burundi, the Rift Valley, and eastern and northern Kenya. Below-normal vegetation conditions were also observed in southwestern Ethiopia and in extreme southern regions of Somalia. Below-average vegetation in these areas is due to poor March to May rains, in addition to hotter-than-average land surface temperatures. Rangeland resources including pasture and water in these areas are expected to deteriorate rapidly during the June to September hot and dry season. The rest of the region had normal to above-average vegetation conditions in the second half of June. Much of the eastern Horn remained relatively cool and dry through June, especially over the highland regions of Kenya, Tanzania, Ethiopia, and southern Sudan. These conditions are likely to continue during the normally cool months of June through August.

The short-term rainfall forecasts for the next two weeks indicate the continued transition to the June to September dry season in most parts of the eastern Horn and Tanzania, and in Rwanda and Burundi (Figure 3). Moderate to heavy rains are expected to continue over much of South Sudan, southern and central Sudan, western and northeastern Ethiopia, and western Eritrea. Moderate to heavy rainfall is also forecast over parts of western and Rift Valley regions of Kenya and northern Uganda. Rains in western and central Kenya and the Rift Valley will continue to ease the current drier-than-normal conditions, especially over the Narok and Kajiado districts of Kenya, and in the Mara region of Tanzania. East Africa coastal areas are also likely to continue receiving light to moderately heavy rains during this period, especially along the coastal areas of Kenya, Tanzania and southern Somalia.

With the increased likelihood (70 to 80 percent) for a moderate El Niño event in the coming months—which is expected to last through early 2015--the rainfall outlook for July to August raises new concerns of average to below-average rainfall over parts of the northern sector of the Greater Horn of Africa, especially eastern Sudan and South Sudan, northern Ethiopia and the neighboring regions of western Eritrea.