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Deyr rains performed poorly in October in southern Somalia, with increases in early November

  • Seasonal Monitor
  • East Africa
  • November 10, 2017
Deyr rains performed poorly in October in southern Somalia, with increases in early November

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  • Key Messages
  • Seasonal Progress
  • Forecast
  • Partner
    Key Messages
    • The onset of the Deyr (October to December) season was significantly delayed over parts of southern and central Somalia by 20-30 days. Rainfall totals in October were less than 50 percent of average, following by increases in rainfall during the first 10 days of November. Seasonal performance has been better in neighboring areas Ethiopia, where rainfall has been average to above average.  

    • Seasonal rainfall since mid-October has been largely above average across broad areas of western and northern Kenya, Uganda, northeastern DRC, and northwestern Tanzania. Meanwhile, rainfall in southeastern Kenya, much of Burundi, and eastern DRC was below average. 

    • During the coming 1-2 weeks, moderate to heavy rainfall is expected over southern and central Somalia, and parts of southeastern Ethiopia and northeastern Kenya. However, due to the delayed start of season in southern Somalia, crop growth in rainfed areas may be impacted by the shortened length of the growing season. Meanwhile, heavy rainfall is forecast over much of Uganda, western areas of Rwanda and Burundi, northeastern DRC, and northwestern Tanzania and Kenya. 

    Seasonal Progress

    The performance of Deyr (October to December) seasonal rainfall has been mixed in the eastern Horn of Africa. The onset of Deyr rainfall was significantly delayed, by 20 to 30 days, over parts of southern and central Somalia where much of Deyr rainfall (50 percent of its seasonal totals), typically occurs in October. In these areas, rainfall in October was less than 50 percentage average, but following by increases in rainfall during early November. Meanwhile, in neighboring areas of southeastern Ethiopia,  seasonal rainfall totals are mostly near or above average. In northeastern and eastern Kenya, where short/Deyr rains typically get underway slightly later, rainfall has been slow to become established and early season rainfall deficits (-10 to -50 mm) have begun to develop.  

    Meanwhile, much of western Rwanda, eastern Burundi, and eastern DRC, were drier than normal during the past two to three weeks. Although the seasons have begun with some cumulative deficits, the rainfall amounts received have been generally sufficient for cropping. 

    Vegetation conditions are above average over large areas of eastern and southern Sudan, much of South Sudan, western and central Ethiopia, northeastern Uganda, and western Kenya, according to the eMODIS/NDVI (Figure 2). However, significantly below-average conditions have persisted across Somalia, southeastern Ethiopia, northeastern Kenya, parts of western Sudan, much of eastern DRC, parts of central and western Rwanda, and western Tanzania. 

    Cropping conditions are expected to remain mostly favorable in Ethiopia Meher-dependant areas and in South Sudan, although FAW is a concern in both and conflict in South Sudan is likely inhibiting agricultural activities. Harvest prospects in most agricultural areas of Sudan are also expected to be normal, following the above-average seasonal rainfall performance. However, below-average rains in Kassala, northern Gadaref, and parts of North Kordofan and North Darfur are likely to result in below-average yield prospects in those areas. In Kenya, the extention of seasonal rainfall beyond September and into October has been largely beneficial for cropping prospects in North Rift Valley counties, but has constrained harvesting and drying activities for maize and is likely to lead to losses. 

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

    • In Somalia, the onset of Deyr rainfall was been significantly delayed by 20-30 days in parts of southern Somalia, with October rainfall totaling less than less than 50 percent of average monthly amounts. However, rainfall increased substantially during the first 10 days of November and according to ARC2 rainfall estimates, seasonal totals may be as high as 80 percent of average. Following these rains, seasonal totals in southern Somalia appear to be at least 80 percent of average, although additional satellite-derived estimates should help assist with a convergence of evidence in the coming weeks.  In addition, the significantly delayed and below-average start to the season is likely to reduce the window for rainfed crop growth and development during the Deyr season NDVI indicates significantly below-average vegetation conditions across large areas of southern Somalia, likely in response to poor October rains and the cumulative impacts of prolonged dryness across the eastern Horn since last year. FAW infestations have been reported in parts of southern Somalia, but its impacts have not yet been fully assessed. In northern Somalia, rainfall performance has remained near average, with minor rainfall deficits as the seasonal rains progress southwards. 
    • In southern and southeastern Ethiopia, performance of the Deyr/Hagaya rains in October has been largely above average to average (+10 to +100 mm). Rainfall in October was spread over a fewer number of days than usual (approximately 10 days in eastern areas), but in early November, rainfall increased in frequency and intensity. Good performance of seasonal rainfall should contribute to improvements in pasture and water availability for livestock. According to NDVI, vegetation levels have increased across much of Somali region, southern Oromia, and eastern SNNPR, but vegetation levels remain below average. 
    • In Kenya, the short rains began slowly in eastern and northeastern areas (Wajir, Garissa, Mandera, and Kilifi), with little rainfall until late October. During the first 10 days of November, seasonal rainfall increased substantially and has reduced rainfall deficits. In these areas, particularly Mandera, vegetations remain well below average, according to NDVI. By contrast, in northwestern areas of Kenya, including Turkana, West Pokot, and Baringo, vegetation conditions are well above average as a result persistently above normal off-season rainfall since July. These off-season rains have also occurred over the main maize growing areas of the northern rift valley (Trans-Nzoia and Uasin-Gishu) and have constrainted harvesting and drying of crops. Meanwhile, the early onset of seasonal rains by 10-20 days, in central-and south-rift valley, including central counties of Kenya, have resulted in early crop planting.
    • In Uganda, rainfall since mid-October has been mostly above average, except in central areas where rainfall was below average. The bulk of the second season harvests are expected between late November and January. Meanwhile, flood and mudslides risks remain high over the recently flooded Mt. Elgon regions. FAW infestations remain a concern in Napak and Luwero districts.  
    • In Sudan, the harvesting and dry season is expected to set in November, with agricultural production prospects expected to be average in most areas of Sudan, except in Kassala and the northern parts of Gedaref, North Darfur, and North Kordofan States, where the June to September seasonal rainfall was erratic and largely below average. FAW infestations are also reported in Gadaref, Blue Nile, and Sennar states, which could result in damage to crops.
    • In South Sudan, seasonal rainfall in October was well above average in eastern regions, below-average rainfall in southwestern and northwestern areas, and near normal amounts elsewhere. NDVI suggests vegetation conditions are mostly average or above average, except in localized areas of Eastern Equatoria, northwestern Jonglei, and northern Upper Nile, where vegetation conditions are below average. 
    • In much of Burundi, eastern Rwanda, and parts of eastern DRC, rainfall since early October has been below average. The crop status is at the emergence to early vegetative stages, but in favorable condition. Vegetation conditions are generally near average for much of these three countries, with a few localized areas of below average conditions.


    During the next two weeks, short-term forecasts indicate moderate to heavy rainfall (40-125 mm) is likely over southern and southeastern Ethiopia, southern and central Somalia, and northeastern and southwestern Kenya (Figure 3). However, due to the current cumulative seasonal deficits in October for much of southern Somalia, there is increased concern about the possibility of overall poor seasonal performance, with a shortened length of the crop growing period. Historical analysis of previous Deyr seasons’ performance show that there is a strong correlation between below-average rainfall in October and below-average seasonal rainfall totals in Somalia and southeastern Ethiopia. Consequently, there is increased need for close monitoring of the current season’s performance, particularly owing to the fact that the region has already experienced 3-4 successive poor rainy cropping seasons. Meanwhile, light rains are expected to continue over the Ethiopian highlands and western Yemen. There is an increased likelihood for rainfall to intensify and spread across the Kenya, Uganda, Rwanda, Burundi, eastern DRC, northern and parts of eastern and western Tanzania in the coming 1-2 weeks. There are heightened flood risks over Kenya/Tanzania’s coastal strip this week and over the Mt. Elgon regions of western Kenya/eastern Uganda. Meanwhile much of Tanzania, will remain typically sunny and dry during this month.

    Figures Figure 1. ARC2 seasonal rainfall estimate anomalies, difference from normal (1983-2009),  October 11-November 9, 2017

    Figure 1

    Figure 1. ARC2 seasonal rainfall estimate anomalies, difference from normal (1983-2009), October 11-November 9, 2017

    Source: Source: NOAA/NWS/CPC

    Figure 2. eMODIS/NDVI anomalies (2007-2016), October 21- 31, 2017

    Figure 2

    Figure 2. eMODIS/NDVI anomalies (2007-2016), October 21- 31, 2017

    Source: USGS/FEWS NET

    Figure 3. Week 1 GFS-Rainfall forecast (mm), valid November 6-13, 2017

    Figure 3

    Figure 3. Week 1 GFS-Rainfall forecast (mm), valid November 6-13, 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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