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Moderate to heavy rainfall in late April may alleviate dry conditions, but is forecast to subside in May

  • Seasonal Monitor
  • East Africa
  • April 26, 2019
Moderate to heavy rainfall in late April may alleviate dry conditions, but is forecast to subside in May

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  • Key Messages
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    Key Messages
    • Below-average rainfall over the past month has exacerbated drought conditions in equatorial East Africa and the Horn. This has delayed or impeded crop production in many agricultural and agropastoral areas and resulted in significant vegetation and surface water deficits that have impacted livestock production

    • Meanwhile, the southwestern, central, and northeastern regions of Ethiopia together with much of southern Tanzania continued to receive average to well above rainfall amounts for past months. In Sudan, conditions remained seasonally dry in the north but vegetation remains in good condition.

    • The forecast through May 2nd is expected to bring widespread moderate to heavy rainfall much of the region, driven by the presence of Tropical Cyclone Kenneth over Mozambique and Tanzania. This is anticipated to bring partially replenish pasture and water availability, especially over Kenya, southern and southeastern Ethiopia, and southern Somalia. However, there is also an increased likelihood of flooding over coastal regions and typical flood-prone areas such as the Mt. Elgon region.


    During the past month, from March 21 to April 20, rainfall performance has been well below average across equatorial East Africa. This is typically the peak period of the March to May seasonal rains in this region. However, the seasonal rains were yet to be fully established in these regions, which continued to experience prolonged dryness and hotter-than-normal weather conditions. Areas that are worst affected by rainfall deficits include northern Tanzania, most of Kenya, northeastern Uganda, southern and central Somalia, and southeastern Ethiopia, which received less than 50 percent of the long-term average (Figure 1). In some parts of southeastern Kenya and southern Somalia, deficits were less than a quarter of average rainfall. Although Rwanda, Burundi, and parts of southern Uganda also experienced below-average rainfall, but deficits were less severe, with rainfall ranging from 76 to 90 percent of average. Conversely, southern and parts of central Tanzania, as well as the southwestern, central, and northeastern Belg-cropping regions of Ethiopia, received average (91-110 percent) to above average (>110 percent) rainfall amounts during this period.

    The overall poor performance of the Gu/long rains season is due to the presence of the continued, disruptive presence of tropical storms/depressions and cyclones over the past two months. There are early indications of another tropical cyclone occurring along the Mozambique Channel this week. However, its forecast track could be beneficial, as it is anticipated to bring widespread rainfall to anomalously dry regions of East Africa. Heavy rains and high winds are currently occurring over parts of southern Tanzania, Mozambique and neighboring countries.

    The impact of the poor seasonal rains combined with exceptionally hotter-than-normal conditions are severe and extensive, evidenced by rapidly deteriorating pasture conditions, water stress in early-planted crops, and depleted surface water across Kenya, southern and parts of eastern Ethiopia, southern and central Somalia, northeastern and central Uganda, and southern South Sudan. Based on the eMODIS/Normalized Difference Vegetation Index, there are extensive areas of significantly drier-than-normal vegetation conditions across many areas (Figure 2). However, in much of the northern sector of East Africa – namely Sudan, parts of South Sudan, and western Ethiopia – vegetation has continued to remain favorable with greener-than-normal conditions.

    Recent FEWS NET and Food Security and Nutrition Working Group (FSNWG) reports indicate that the region is experiencing drought conditions, which are likely to persist until the end of the March to May season, despite the forecast of increased rainfall in the coming weeks. The anticipated increase in rainfall in the final week of April through May would be too late in the season to aid crop recovery in many areas, resulting in a significantly increased likelihood of below-average maize crop production and below-average rangeland resource recovery across the eastern Horn. However, the rains would bring short-term relief in terms of slight surface water recharge and partial regeneration of pasture and browse in pastoral and wildlife zones.

    The following is a country-by-country update on recent seasonal progress to date:

    • In Somalia, April was generally dry and hotter-than-normal, with only uneven and very localized light to moderate rains in Bay and Shabelle regions in the South and in parts of the northwest. The amounts were well below average in the South, particularly over the sorghum belt. Cumulative deficits ranged from -50 to -100 mm in a critical period of crop planting and development. The below-average rains have depleted rangeland resources and led to rising water scarcity, with increasing concern for a below-average cropping season despite the establishment of the Gu rains this week in agropastoral regions.
    • In Ethiopia, the Belg rainfall season has progressed largely favorably in the southwestern, central, and northeastern regions due persistently average to above-average rainfall amounts, though localized flash floods were reported over central Ethiopia. Agricultural conditions are conducive to crop development in key Belg-cropping regions of Tigray, Amhara, Oromia and SNNPR. In southern and eastern regions, rains have been generally erratic and below average. As a result of poor rainfall in these areas, drier-than-normal vegetation conditions and depletion of surface water pans are observed, predominantly in pastoral livelihood zones. However, Genna and Gu rainfall has substantially increased in the past week across southern Oromia and much of Somali region.
    • In Kenya, the performance of the long rains has been well below average (less than 50 percent), especially in April. Worst affected areas are located in Kajiado, Narok, Kitui, Makueni and parts of southern Turkana and West Pokot counties, which have received less than 25 percent of average in the March 21-April 20 period. In eastern and southeastern marginal agricultural zones, maize planting was significantly delayed by a month and there is an increased likelihood that rains will cease in May. This effectively reduces the length of maize-growing period by more than a month, which is expected to result in deficits greater than 50 percent, though other short-cycle grains, legumes, and fodder could yet produce near-normal amounts. In high potential agricultural areas in western, Rift Valley, and central counties, rainfall has not yet been sufficient to support widespread planting and crop development.
    • In Sudan, April is typically a dry and hot month. Occasionally, light to moderate rains can occur in May over its southern regions bordering South Sudan. Despite the ongoing dry season, vegetation conditions have remained largely favorable, due to heavy seasonal rains in June late last year.
    • In South Sudan, vegetation conditions have remained generally favorable, except in southern bimodal areas where seasonal rainfall from late March into mid-April has been below average (<75 percent).  
    • In Uganda, early-planted crops were severely affected by water stress due to insufficient rainfall accumulation and prolonged dry spells in March and April. Much of the country has yet to receive sufficient rainfall to support widespread crop planting and development, especially in the eastern and central districts. However, it is expected that current moderate to heavy rains will lead to more planting, though late in the season.
    • In Rwanda and Burundi, season B rainfall performance has gradually improved over the past month with near-average rainfall amounts. However, parts of southeastern Burundi have continued to receive below-average rainfall. Current rainfall performance has been largely beneficial and fairly favorable for both cropping and rangeland conditions, with the exception of localized areas of concern in the eastern districts of Rwanda and Burundi bordering northern Tanzania.
    • In Tanzania, 2018/19 Msimu rains have generally been favorable, with consistently above-average rainfall amounts in the unimodal southern regions and in parts of its central and western regions. These regions have good prospects for normal production this season. However, there is an increased likelihood of flooding in the southern and eastern coastal regions in the coming week due to the development of Tropical Cyclone Kenneth, which is forecast to make landfall in this area. Meanwhile, bimodal northern regions have continued to receive uneven and below-average rainfall, with deficits akin to that in neighboring southern Kenya.
    • In Yemen, March to May seasonal rainfall performance has largely been below average, with localized areas of average to above average in the western highlands.


    The one-week rainfall outlook shows an increased likelihood for widespread, moderate to locally very heavy seasonal rains across East Africa (Figure 3). Tanzania, Rwanda, Burundi, Uganda, Kenya, and southern Somalia, as well as southern Belg-dependent cropping zones and southern pastoral zones of Ethiopia, are forecast to benefit from this rainfall. Looking further forward, the western and northern sector of the region are forecast to continue experiencing moderate to rains into May. Conversely, the rains are forecast to be episodic and short-lived across the eastern Horn, subsiding into dry spells in early May, especially in Kenya, eastern Ethiopia, and southern Somalia.

    The path of Tropical Cyclone Kenneth is forecast to affect the vicinity of the East Africa coastal region from April 23-27. It is likely to enhance rainfall across East Africa during this period, until the storm dissipates over Mozambique. Conditions require close monitoring, given a likelihood of very heavy rains and high winds in southeastern regions of Tanzania into northeastern Mozambique. The rains could become more widespread and be favorable for East Africa, but the tropical cyclone could also result in localized floods in parts of the Mt. Elgon region (Uganda and Kenya), southern Kenya, northern Tanzania, southern Somalia, and the southern and eastern lowlands of Ethiopia.

    The forecast of moderate to localized heavy rains through May 2nd may ease current land surface temperatures and alleviate the severity of dryness in pastoral areas. Should this forecast materialize, pasture and water resources would be partially replenished in the agropastoral regions of southern and southeastern Ethiopia, agropastoral and pastoral zones in northern and parts of southern Kenya, parts of southern Somalia, and Uganda. Cropping conditions could also improve in Uganda, northern Tanzania, southern South Sudan, and southern Somalia. In Belg-regions of northern Ethiopia, however, the approach of the tropical cyclone is likely to weaken the amount and spatial distribution of rainfall.

    Looking toward the end of the season, the preliminary monthly forecast from the national and regional meteorological services show an increased likelihood of a normal cessation of the long rains over parts of the eastern part of the Horn by May. This excludes Somalia, where the rainfall season lasts through June, and coastal regions, which typically receive peak rainfall amounts in mid-May through June.

    Figures Rainfall was less than 50 percent of normal in south-central Somalia, southeastern Ethiopia, most of Kenya, northeastern Ugan

    Figure 1

    Figure 1

    Source: FEWS NET/USGS

    Deficits of 20 to 40 percent or more are pervasive in northern Uganda, Kenya, southern Somalia, and central and southern Ethi

    Figure 2

    Figure 2

    Source: FEWS NET/USGS

    The one-week rainfall outlook shows an increased likelihood for widespread, moderate to locally very heavy seasonal rains in

    Figure 3

    Figure 3

    Source: NOAA/CPC

    FEWS NET’s Seasonal Monitor reports are produced for Central America and the Caribbean, West Africa, East Africa, Central Asia, and Somalia every 10-to-30 days during the region’s respective rainy season(s). Seasonal Monitors report updates on weather events (e.g., rainfall patterns) and associated impacts on ground conditions (e.g., cropping conditions, pasture and water availability), as well as the short-term rainfall forecast. Find more remote sensing information here.

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