The workshop reviewed the state of the global climate system and its implications for the sub-region. Among the principal factors taken into account were the evolution patterns of the sea-surface temperature anomalies over various parts of the global Oceans including the warmer than normal sea surface temperatures (SSTs) that have been observed over western Indian and tropical Atlantic Oceans as well as SSTs anomalies over other parts of the global oceans. Global Ocean model outputs by most of the advanced climate centres indicate likelihood for neutral to La Niña conditions during the period that the outlook is being given . Products from coupled ocean-atmosphere models and physically based statistical models from several major climate centres were also considered in the development of the workshop consensus climate outlook. The centres whose products were utilised include DMCN, University of Nairobi, the International Research Institute for climate prediction (IRI); National Oceanic and Atmospheric Administration/National Centers for Environmental Prediction (NOAA/NCEP); European Centre for Medium Range Weather Forecasts (ECMWF) and the United Kingdom Meteorological Office. The workshop participants 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 on 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.

The current status of seasonal-to-interannual forecasting allows prediction of spatial and temporal averages, and may not fully account for all factors that influence regional and national climate variability.

OUTLOOK

June to September constitutes a major rainfall season over much of the northern sector as well as the coastal and western equatorial parts of the sub-region. The rainfall outlook for each zone within the sub-region is provided below.
 
 

  Consensus June to September 2003 Climate Outlook for the Greater Horn of Africa

Zone II: Enhanced probabilities of near to above normal rainfall over central and eastern Sudan as well as western Ethiopia.

Zone III: Increased likelihood of near to below normal rainfall over central Eritrea, western Djibouti as well as central and northeastern Ethiopia.

Zone IV: Enhanced probabilities of near to above normal rainfall over eastern Eritrea, eastern Djibouti, central and northern Somalia as well as eastern Ethiopia.

Zone V: Increased likelihood of near to below normal rainfall over southern coast of Somalia and northern coast of Kenya.

Zone VI: Enhanced probabilities for near to above normal rainfall over the southern coast of Kenya and northern coast of Tanzania.

Zone VII: Climatology is indicated over much of Tanzania and Kenya as well as southern Ethiopia and southwestern Somalia.

Zone VIII: Enhanced probabilities for near to below normal rainfall over southwestern Sudan, parts of Lake Victoria Basin, northern and southern Uganda, Rift Valley and southwestern Kenya as well as much of Rwanda and Burundi.

Zone IX: Increased likelihood of near to above normal rainfall over much of Uganda and western Kenya.

This outlook is relevant only for seasonal time scales and relatively large areas. Local and month-to-month variations may occur. The National weather services and the DMCN provide update forecasts. 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