Consensus outlook derived from prediction models from ICPAC and other climate centres indicate that there is increased likelihood of near to below normal rainfall over much of the Greater Horn of Africa during the period March to May 2005. However probabilities of near normal to above normal rainfall favour central and northern Tanzania; Burundi; Rwanda; southern Uganda; central and southern Kenya eastern Djibouti; northeastern and western Ethiopia as well as eastern Sudan. It should be noted that episodic intense short rainfall events may occur even in areas with a likelihood of near to below normal rainfall.
The outlook is relevant only for
seasonal time scales and relatively large areas. Local and month-to-month
variations may occur. Forecast model outputs indicate transition from mild El
Niño to neutral conditions over the equatorial
Update forecasts are provided by the National Weather Services and the IGAD Climate Prediction and Applications Centre (ICPAC). The users are therefore strongly advised to keep in contact with their National Meteorological Services for interpretation of this outlook, finer details, updates and additional guidance.
From 2 to
The forum examined the current and
expected SST anomalies over the
The experts established probability distributions to indicate the likelihood of above-, near-, or below-normal rainfall for each zone (see Map). Above-normal rainfall is defined as within the wettest third of recorded rainfall amounts in each zone; near-normal is defined as the third of the recorded rainfall amounts centred around the climatological median; below-normal rainfall as within the driest third of the rainfall amounts. Climatology refers to a situation where any of the three categories have equal chances of occurring.
March to May constitutes an important rainfall season over the equatorial parts of the Greater Horn of Africa sub-region. The rainfall outlook for each zone within this sub-region is given below.
Greater Horn of
Zone I: Increased likelihood of near to below-normal
rainfall over southern and southwestern
Zone II: Increased
likelihood of above to near normal rainfall over central and northern
Zone III: Increased
likelihood of near to below-normal rainfall over much of
Zone IV: Increased
likelihood of near to above- normal rainfall over eastern
Zone V: Increased likelihood of near to below normal
rainfall over northwestern
Zone VI: Climatology is indicated over northern
The numbers for
each zone indicate the probabilities (chances of occurrence) of rainfall in
each of the three categories, above-, near-, and below normal. The top number
indicates the probability of rainfall occurring in the above-normal category;
the middle number is for the near normal and the bottom number for the
below-normal category. For example, in case of southern and southwestern
The fifteenth climate outlook forum for the Greater Horn of Africa was organised jointly by the IGAD Climate Prediction and Applications Centre, Nairobi (ICPAC), National Meteorological and Hydrological Services (NMHSs), the World Meteorological Organisation (WMO) and the International Research Institute for climate prediction (IRI) within the framework of the United States Agency for International Development (USAID) funded project “Sustainable generation and application of climate information, products and services for disaster preparedness and sustainable development in the Greater Horn of Africa”.
to this consensus climate outlook included representatives of the
Meteorological Services from ten GHA countries (Insititut Geographique du
Burundi; Meteorologie Nationale de Djibouti; Eritrea Meteorological Services;
National Meteorological Services Agency of Ethiopia; Kenya Meteorological
Department; Rwanda Meteorological Services; Somalia meteorological services,
Sudan Meteorological Authority; Tanzania Meteorological Agency and Uganda
Department of Meteorology) and climate scientists as well as other experts from
national, regional and international institutions and organisations (IGAD
Climate Prediction and Applications Centre; Drought Monitoring Centre, Harare; International
Research Institute for Climate Prediction (IRI); World Meteorological
Organisation (WMO); USGS/FEWS-NET; University of Nairobi).
Additional input was supplied by the National Centers for Environmental
Prediction/Climate Prediction Center (NCEP/CPC),