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N° 955
Greater Horn of Africa Climate Outlook Forum assesses coming rainy season
Zanzibar/Geneva, 3 September 2012 (ICPAC/WMO) - The Greater Horn of
Africa Climate Outlook Forum has concluded that, in the forthcoming
September-December rainy season, most parts of the region are likely to
receive near normal to above normal rainfall.
The Forum issued a consensus-based regional climate outlook following a review of the current and
expected future state of the global climate system, large-scale climate anomalies and their
implications for the 11 countries in the Greater Horn of Africa region. Meteorological experts as well
as representatives from disaster risk management, water resources, agriculture and food security,
health and development sectors were among the participants. The forum session held from 29 to 31
August 2012 in Zanzibar, United Republic of Tanzania, was convened by the Intergovernmental
Authority on Development’s Climate Prediction and Applications Centre (ICPAC) with the support of
the World Meteorological Organization (WMO) and other partners, and hosted by the Tanzanian
Meteorological Agency.
September to December constitutes the second most important rainfall season, after the March-May
rainfall season, over southern Somalia and other equatorial parts of the Greater Horn of Africa
(Kenya, Uganda, Burundi, Rwanda and northern Tanzania).
The climate outlook indicated “increased likelihood of near normal to above normal rainfall” over most
of the equatorial sector, including areas east of the Great Rift Valley, and the Great lakes sub-region
including Southern Sudan and parts of Ethiopia during September to December 2012.
It cited the evolution of a positive Indian Ocean Dipole characterised by warmer than average sea
surface temperatures over Western Indian Ocean and Arabian sea, the likelihood of a weak El Niño
developing towards the end of 2012, and the evolution of large and regional scale moist atmospheric
circulation.
“The severe drought in Somalia and adjoining areas in 2010/2011 and subsequent flooding in other
parts of the region highlight the vulnerability of the Greater Horn of Africa to weather and climate,”
said WMO Secretary-General Michel Jarraud. “The regional climate outlook forum is an important tool
to support socio-economic development in participating countries and help policymakers, water
managers, disaster risk sector and farmers plan ahead,” he said.
The climate outlook forum is an example of one of the purposes of the Global Framework for Climate
Services to ensure timely interaction between users and providers of climate information and
providing the best science-based information for decision-making. An extraordinary WMO Congress
(29-31 October 2012) is scheduled to approve the implementation plan for the Global Framework for
Climate Services.
The outlook is relevant for seasonal time scales and relatively large areas. Local and month-to-month
variations might occur. Forecast updates will be regularly provided by ICPAC and the respective
National Meteorological and Hydrological Services. The users are therefore strongly advised to
contact their National Meteorological Services for national and local details.
World Meteorological Organization is the United Nations System’s authoritative voice on Weather,
Climate and Water
Rainfall Outlook for September to December 2012
The rainfall outlook for various zones within the Greater Horn of Africa region is given in figure 1 below.
Zone I, II, III, IV, V, VII: Increased likelihood of above normal to near normal rainfall
Zone II: Climatology (normal conditions for the season being projected)
Zone VI: increased likelihood of near normal to above normal rainfall.
Figure 1: Greater Horn of Africa Consensus Climate Outlook for the September to December2012 rainfall
season
The numbers for each zone indicate the probabilities of rainfall in each of the three categories, above,near-, and below-normal. The top number indicates the probability of rainfall occurring in the abovenormal category; the middle number is for near-normal and the bottom number for below-normal
category. For example, in zone VI, there is 35% probability of rainfall occurring in the above-normal
category; 40% probability of rainfall occurring in the near-normal category; and 25% probability of
rainfall occurring in the below-normal category. It is emphasised that boundaries between zones ould
be considered as transition areas.
Figure 2 : The September to December (SOND) long term average (LTM) rainfall based on
1961-1990.
WMO website: www.wmo.int
For more information, please contact: Clare Nullis, Press Officer, Communications and Public Affairs, Tel: +(41
22) 730 8478; 41-79) 7091397 (cell), e-mail: cnullis(at) wmo.int .