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55, Avenue des ministeres PPL6 BP: 13 184 Niamey - Niger
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Fax: 2272072327
Email: contact@acmad.org
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REGIONAL CLIMATE OUTLOOK FORUM FOR WEST AFRICA, CHAD and CAMEROON

This region typically covers the area between the Sahara desert in the north and the tropical Atlantic coast to the south. The regional climate is dominated by the West African monsoon during the rainy season typically occurring during northern hemisphere summer (from July to September).

Major sources of seasonal climate variability and predictability in the region include Sea Surface Temperatures (SSTs) of the equatorial Pacific (ENSO region), the Mediterranean Sea, the tropical Atlantic Ocean (North and South) as well as the Western Equatorial Indian Ocean.  SST predictive skill is limited over most ocean basins except the ENSO region.  It is recognized that soil moisture is another important source of climate variability and predictability over the region. Uncertainties on SST forecasts over the Mediterranean Sea, the tropical Atlantic and equatorial Indian Ocean, soil moisture forecasts over land areas of the region are documented. 

Improvement of ocean models over the tropical Atlantic, land surface models over sub-Saharan Africa and coupled ocean-atmosphere-land models are required to provide better inputs to operational seasonal prediction for the region.

Floods and droughts, late onsets, early and late cessation of rains, dry and wet spells are the main climate hazards of the region. Shortage of water, multiple sowing, food insecurity due to reduction in crop yields, conflicts between farmers and herders due to droughts, epidemic malaria regularly occur. Roads and other infrastructure damages, loss of lives and properties associated with floods have become a matter of strong concern in many cities of the area since the late 90s.

The RCOF

The RCOF started in 1998. It has been held once a year usually in May with July-August-September as the main target season. Following request of users, It has started in 2014 to be held in late April to increase lead time and usefulness of the product.  It involves 17 countries in West and Central Africa namely Mauritania, Senegal, Mali, Guinea-Bissau, Guinea, Côte d’Ivoire, Burkina Faso, Niger, Chad, Cameroon, CAR, Nigeria, Benin, Togo, Ghana, Liberia, Cape Vert. National Meteorological and Hydrological services of the region, WMO Global Producing Centres for Long Range Forecasts, AGRHYMET Regional Centre are the major collaborating partners.

Figure a and b : Seasonal Precipitation forecasts for the Sudano-Sahelian region of Africa; for June July August and July August 2023

Figure c : Regional Brief for Policy and Decision Makers; for June to September 2023

The approach involves assessment of outputs from global single and multimodel ensemble forecasting systems, statistical seasonal forecasting tools, analogue years, persistence, composites and trends analysis as well as available findings from climate studies at local, national, regional and global levels. Interpretation of models outputs rely on relevant verification products. The assessment made is discussed during a briefing and a consensus outlook generated for users. Sessions for hydrologists are organized in parallel generating discharge outlooks presented at the forum plenary.

The African Centre for Meteorological Applications for Development (ACMAD) is the main coordinating institution. It is the Long Range Forecasting node of the proposed ECOWAS-RCC network. The AGRHYMET Regional centre is responsible for discharge outlooks and agrometeorological advices based on precipitation outlook.

Contact details: African Center of Meteorological Applications for Development , ACMAD, 55, Avenue des Ministères, PL6, BP 13184, 1er Arrondissement, Niamey Plateau, Niger, Tél: (+227) 20734992; Fax: (+227) 20723627. Email: climat@acmad.org, website: www.acmad.org/rcc

User involvement

Users from agriculture, water, health, disaster management and media communities are invited to the forum for exchanges, interactive discussions on the historical, current and expected climate conditions, related impacts, advices and recommendations to cope with negative impacts or increase benefits linked to possible opportunities due to favorable climate conditions.

Success stories based on feedback of users

In 2008, ACMAD issued an update of consensus prediction for the region with high probability ( up to 50%) for above average rainfall over much of the southern Sahel. Wet to very wet years in the region are usually associated with higher frequency of heavy rains and floods. The forecast was used for an appeal by Red Cross for funding for flood preparedness. The funds were granted leading to prepositioning of relief items (mosquito nets, blankets…). Without this forecast, items would have been provided after floods. The efforts would have then cost more in time and transport expenses. This was the first time in Red Cross’s history that based on seasonal forecasts, funds were requested and used to prepare for potential emergency. Wet years are also related to more mosquitoes and malaria in Sub Saharan Africa. UNICEF office in Niger used seasonal forecasts to prepare and preposition drugs and mosquito nets for vulnerable communities.

Way forward

Scientific research on ocean-land-atmosphere modeling, new predictors for statistical forecasting tools, local and regional climate variability and trends studies, assessment of regional performance of forecasting systems including their strengths and weaknesses in predicting regional climate processes and phenomena are proposed to improve consensus outlook products. Predictions at subseasonal timescales and advances in seamless prediction are ongoing efforts to improve forecasts of anomalous onset and cessation of the rainy season, wet and dry spells during the rainy season. For medium to long term policies and plans, climate scenarios and decadal climate forecasts, related impacts and vulnerability assessments are required as outputs of future RCOFs for use in climate change adaptation programmes.

Participation of climate service providers in user forums namely contingency planning meetings, agriculture season planning workshops, vulnerability assessment and water forums is important for effective and wide exchanges, interactions and consensus building on sector relevant impacts, adaptation measures, advices and recommendations. Provision of climate outlook in April instead of May each year and for May to October as target season is needed for further engagement of a wider range of users and expansion of forecasts application opportunities.

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