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Seasonal rainfall slow to start in southern Ethiopia and Kenya

  • Seasonal Monitor
  • East Africa
  • March 31, 2017
Seasonal rainfall slow to start in southern Ethiopia and Kenya

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  • Key Messages
  • Seasonal Progress
  • Forecast
  • Partner
    Key Messages
    • March to May rainfall has been slow to get fully underway in parts of the Eastern Horn, with a delayed and/or below-average start to seasonal rains in pastoral and agropastoral areas of southern Ethiopia and northeastern Kenya, and below-average Belg rainfall in Ethiopia during March. Likewise, March rainfall was also below average in southern Kenya, northeastern Tanzania, parts of much of Rwanda. 

    • Rainfall during the month of March was generally normal to above average in much of Tanzania, Uganda, and Burundi, although decreases in rainfall in Uganda since mid-March have led to some moisture stress on crops in bimodal areas.

    • Vegetation conditions remain well below average across large areas of southern and central Somalia, southern Ethiopia, and most of Kenya, and parts of Tanzania, following well below-average performance of the October to December rains and a start of season that is already delayed in areas where seasonal rains typically increase starting in mid-March. 

    • Short-term rainfall forecasts indicate an increase in rainfall over the coming weeks, particularly in parts of Tanzania, Burundi, and Rwanda. However, forecasts suggest rainfall over the eastern Horn will likely be erratic and light in amounts, leading to the possibility of an erratic or delayed start of season, including in Somalia and eastern Ethiopia.

    Seasonal Progress

    Overall performance of March rainfall in the region has been mixed over the past month. Many areas of the Eastern Horn, including most of Somalia, and many areas of eastern Ethiopia, remain drier than normal in advance of the onset of seasonal rainfall in April. In pastoral areas of southern Ethiopia and northeastern Kenya where seasonal rainfall typically begins by mid-March, seasonal rainfall has been below average and is already considered delayed by one to two weeks. This prolonged dryness continues to significantly limit water and pasture for pastoral households and is unfavorable for cropping in agropastoral areas. In addition, Belg seasonal rainfall has been below average in many Belg-receiving areas of Ethiopia.

    However, there was an early onset of seasonal rainfall by 10 to 20 days in February over parts of Burundi, Rwanda, Uganda, and western Kenya. The early onset is attributed to a series of tropical cyclones in the neighbouring Indian Ocean resulting in abnormally heavy rains that persisted into early March. These rains were slightly to well above average (+20 to +200 mm) in Tanzania, Uganda, and southeastern South Sudan and neighboring areas of southwestern Ethiopia. However, during the month of March, seasonal rainfall was below-average in Kenya, most of Burundi, parts of western Rwanda, and eastern DRC.  

    According to the Normalized Difference Vegetation Index, vegetation conditions remain well below average across many areas of southern Somalia, southern and eastern Ethiopia, much of Kenya, northern Uganda, western Tanzania, and parts of South Sudan. Persistent cloudiness associated with ongoing rains over Rwanda, Burundi, and northwestern Uganda have partially obscured assessment of vegetation conditions.

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

    • In Ethiopia, the onset of March to May Belg rains have been slow and early season rainfall deficits have accumulated in most Belg-receiving areas of the country. In southern pastoral areas of SNNPR and southern Oromia, the onset of March to May Gu/Genna rains are already delayed by one to two weeks. Large portions of Ethiopia have remained sunny and hot, with the southern and eastern region still under pronounced drier-than-normal conditions. The coming weeks are critical for the establishment and intensification of the seasonal rains in these areas.
    • In Somalia, the January to March Jilaal dry season is ongoing, with pasture and water availability much more limited than normal, following the failure of the preceding October to December 2016 Deyr rains. The Gu rains typically start in April and little to no rainfall is forecast in southern or central Somalia through the end of March. However, 10-80 mm of rainfall is expected over isolated areas of northwestern Somalia during the upcoming weeks.
    • In Kenya, the March to May rainy season has yet become fully established and prolonged severe dryness has further constrained access to water and pasture, which has reportedly led to instances of resource-based conflict. In addition, the delayed onset has led to a delay in planting in marginal agricultural areas.
    • In Tanzania, the significantly improved Msimu unimodal rains over the past one to two months have resulted in improved crop production prospects, especially in southern, higher-producing areas, easing some pressure on already planted crops. However, the significantly delayed start of the season, especially in transition areas of northern Tanzania, is still likely to leading to prospects for lower than normal yields. The start of the Masika (March to May) season in bimodal areas has been near normal with additional rainfall expected in April, which is beneficial following the poor Vuli season.
    • In Uganda, above-average seasonal rains between February and early March led to an early start of season in most bimodal areas. These rains are expected to gradually ease the prolonged drier-than-normal conditions along the cattle corridor. Although early planted crops are in the vegetative stage and cropping conditions are good overall, decreases in rainfall over the past few weeks have resulted in some slight moisture stress on crops.
    • In Rwanda, seasonal rains became established in February, marking an early onset for the key cropping areas of the country. Cropping conditions are normal in eastern parts of the country, but rainfall during March was less than 80 percent of average, and locally less than 50 percent of average, in western areas of the country. The seasonal rains are expected to continue in the coming weeks and are likely to ease dryness.
    • In Burundi, the seasonal start of Season B also occurred in February, which has eased dry conditions in parts of eastern Burundi. Overall, rainfall in March was above average, except in areas of far western Burundi. Cropping conditions are expected to improve with the peak of the seasonal rains in April.
    • In Djibouti, eastern pastoral regions of the country remain drier-than-normal following the slightly below-average Xays/Dadaa (October to February) rainfall season. Recent near average rains for the Diraac/Sugum (March to May) season and forecast rainfall are likely to gradually improve currently poor rangeland conditions in southeastern Ali Sabieh region.
    • In eastern DRC, experienced significant early season rainfall deficits, particularly areas bordering Rwanda and northwestern Burundi. This resulted in slightly below-average vegetation conditions. Current cropping conditions for the early planted crops remain favorable and additional moderate to very heavy rains are forecast in the coming weeks.
    • In Yemen, rain showers in March across western coastal areas of the country were likely favorable for cropping. However, the ongoing political and economic situation, leading to high diesel prices and insecurity, may lead to reductions in some cropping activities.


    The 1-week NOAA/GFS rainfall forecast (Figure 3) through April 5, 2017 indicates an increased likelihood for continued moderate to heavy rains over Tanzania, Eastern DRC, Rwanda, Burundi, parts of western Uganda, some Belg cropping areas of Ethiopia, and southeastern Kenya. These rains are likely to gradually help support crop growth and support generation of rangeland resources.

    However, GFS forecasts for the next one to two weeks indicate most parts of the Eastern Horn, including Somalia, eastern Ethiopia, and eastern and northen Kenya, as well as most of Uganda, are unlikely to receive any significant rains the coming weeks. Particularly in areas of the Eastern Horn where the October to December 2016 rains failed or performed very poorly, these forecasts are concerning. In areas where seasonal rainfall typically gets underway starting in mid-March, such as southern SNNPR in Ethiopia, these forecasts suggest a continued delay in the start of season and potentially signal a delayed or erratic start of season in areas such as Somalia, where seasonal rains typically become established in April. A poor and/or delayed start of season in these areas would lead to an even more prolonged period of dryness during which time pasture and water availability would be depleted or exhausted.

    Figures Figure 1. ARC2 seasonal rainfall estimate anomalies, as percent of normal (1983-2009),  March 1-28, 2017

    Figure 1

    Figure 1. ARC2 seasonal rainfall estimate anomalies, as percent of normal (1983-2009), March 1-28, 2017

    Source: NOAA/NWS/CPC

    Figure 2. eMODIS/NDVI anomaly (2001-2010), March 16-25, 2017

    Figure 2

    Figure 2. eMODIS/NDVI anomaly (2001-2010), March 16-25, 2017

    Source: USGS/FEWS NET

    Figure 3. 1-Week GFS-Rainfall forecast (mm),  valid until April 5, 2017

    Figure 3

    Figure 3. 1-Week GFS-Rainfall forecast (mm), valid until April 5, 2017

    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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