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Little rain forecast during the end of the Deyr/short rains season in the Horn of Africa

  • Seasonal Monitor
  • East Africa
  • December 15, 2017
Little rain forecast during the end of the Deyr/short rains season in the Horn of Africa

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  • Key Messages
  • Seasonal Progress
  • Forecast
  • Partner
    Key Messages
    • The Deyr/short rains season is coming to an end in the Horn of Africa, with little to no rainfall in many areas since mid-November, and little to no rainfall forecast for the next two weeks. Following a significantly delayed start of season and below average seasonal rainfall, below-average crop yields are expected in rainfed areas of southern Somalia and eastern Kenya. 

    • Overall, cropping prospects are near normal in most areas of Uganda, Rwanda, and Burundi, following well distributed and sufficient rainfall during the season. However, rainfall deficits persist late in the season in parts of central Uganda, western Rwanda, Burundi, and neighboring areas of eastern DRC. 

    • Over the next two weeks, moderate to heavy rainfall is forecast over much of Tanzania, Burundi, Rwanda, and eastern DRC. In coastal Kenya, additional rainfall could help to ease seasonal deficits, but may not significantly improve crop yield prospects.  

    Seasonal Progress

    Since mid-November, rainfall has been below average across many areas of the Horn, including southeastern Ethiopia, southern Somalia, and much of eastern Kenya. The onset of the Deyr/short rains season was delayed by almost a month and poorly distributed over time, and cumulative totals have been below average across much of Somalia, eastern Kenya, and western Somali Region in Ethiopia.

    Meanwhile, in much of southern South Sudan, Uganda, Rwanda, Burundi and eastern DRC, cropping conditions have generally remained favorable following the average to above average rainfall between mid-November and early December. However, there are also localized areas of below-average cropping conditions, in response to the poorly distributed and below-average amounts of rainfall in parts of central and northwestern Uganda, western Rwanda and Burundi, eastern DRC, and bimodal cropping areas of northern Tanzania.

    Vegetation conditions are generally above average over much of southeastern Ethiopia, northeastern and eastern Uganda, and northwestern Kenya, according to the eMODIS/NDVI (Figure 2). However, there are extensive areas where vegetation conditions are below average, including southeastern and southern Kenya, and coastal areas of southern Somalia, eastern DRC and western Burundi.

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

    • In Somalia, following heavy rainfall in early November, little rainfall has occurred in Somalia between mid-November and early  December. NDVI suggests vegetation conditions have improved significantly over the past two to three weeks, likely in response to increased rainfall in early November. However, the delayed onset of seasonal rainfall and end of rains in December, the growing period for crops is likely to be much shorter than usual, which is likely to reduce yields in rainfed areas.
    • In Ethiopia, little to no rainfall has occurred in southeastern Ethiopia and rainfall has been below average in southern SNNPR, since mid-November. Overall, seasonal performance has been mixed in these areas, which are largely pastoral. Seasonal performance has been generally above normal in southern SNNPR. Although rainfall totals are above average in far eastern areas of Somali Region, this rainfall was concentrated over a shorter period of time than is typical, occurring largely in early November. Meanwhile in western Somali Region, rainfall has been poorly distributed over time and below average in cumulative amounts.
    • In Kenya, in eastern, southeastern, and coastal counties, such as Kitui, parts of Makueni, Tana River, Taita taveta, parts of Kilifi and Garissa, there are significant rainfall deficits, which is leading to water stress on crops and below-average regeneration of water and pasture resources. Worst-affected areas include Isiolo and northern Tana River, with seasonal rainfall between 40 and 80 percent of average.  
    • In Rwanda, Burundi, and most parts of DRC, following improvements in rainfall in November, rainfall has declined since early December. However, vegetation remain near to slightly below normal for most areas. In Burundi, most of the deficits have occurred in low altitude areas, where late and below-average rainfall affected crop development for Season A. In Rwanda, normal crop growth for Season A crops is reported in most areas.  


    Seasonal rains are likely to continue shifting further southwards into Tanzania and Southern Africa during the coming 1-2 weeks, marking the gradual the end of the October – December rains for much of the Horn of Africa. The GFS rainfall forecast indicates little or no rainfall is expected across Ethiopia, Somalia, and much of northern Kenya.

    Over the next two weeks, substantial rainfall is forecast over much of Tanzania, Burundi, Rwanda, eastern DRC, and parts of southern Kenya. The coastal strip of Kenya (parts of Kilifi, Lamu, Mombasa and Kwale) and Tanzania (entire coastal strip) are likely to receive enhanced rainfall. Tana River, Garissa, and Isiolo counties are likely to facing drier than normal conditions.

    Figures Figure 1. ARC2 seasonal rainfall estimate anomalies, difference from normal (1983-2009),  October 1 – December 10, 2017

    Figure 1

    Figure 1. ARC2 seasonal rainfall estimate anomalies, difference from normal (1983-2009), October 1 – December 10, 2017

    Source: NOAA/NWS/CPC

    Figure 2. eMODIS/NDVI anomalies (2007-2016), December 1-10, 2017

    Figure 2

    Figure 2. eMODIS/NDVI anomalies (2007-2016), December 1-10, 2017

    Source: USGS/FEWS NET

    Figure 3. 2nd Week GFS-Rainfall forecast (mm),  valid December 12 - 18, 2017

    Figure 3

    Figure 3. 2nd Week GFS-Rainfall forecast (mm), valid December 12 - 18, 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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