2013 summer climate outlook for West Africa and Sahel
West Africa and the Sahel region is not expected to experience severe precipitation deficits during the July-September rainy season, according to the seasonal climate outlook issued the African Centre of Meteorological Applications for Development (ACMAD).
Based on the current state and expected evolution of sea surface and sub-surface temperature patterns over the global oceans and their known relationships with the West African climate, as well as statistical and dynamical model outputs and expert judgment, the precipitation outlook for July-August-September 2013 is as follows:
- Near Average or above average precipitation very likely over western Sahel (zone I; see diagram) from Mauritania and Senegal to western and central Niger. About 80% to 130% of normal precipitation is expected over much of this zone.
- Near average or below average precipitation very likely over the Eastern Sahel (zone II) from the Lake Chad area to the middle part of Chad. About 70% to 110% of normal precipitation is expected over much of this area.
- Near average or below average precipitation very likely along the Guinea coast (zone II) from Cameroon to Liberia. About 80% to 110% of normal precipitation is expected over much of the area.
- Climatological expectations for the remaining parts of the domain, mean that above, near or below average precipitation is considered equally likely in the absence of strong predictive signals.
“The region is not expected to experience severe precipitation deficits,” according to the Regional Climate Outlook Forum for West Africa, Chad and Cameroon (Prévisions saisonnières climatiques en Afrique de l’Ouest) at its 16th session held from 27 to 31 May 2013 in Abuja, Federal Republic of Nigeria, and coordinated by ACMAD.
The climate outlook provided advice for users like the agricultural and disaster management communities.
WMO supports ACMAD and is promoting the development of seasonal climate outlooks through Regional Climate Outlook Forums in many regions of the world as part of the Global Framework for Climate Services to increase the availability of user-friendly climate information for decision-makers and local communities alike.
The outlook further says that available experimental products and expert knowledge on sub-seasonal monsoon precipitation variability suggest an increased likelihood for normal to slightly earlier than normal onset of the monsoon over much of the Sahel and disruptions in the distribution of precipitation events during 2013 summer over the region.
Because of the weakness of climate drivers, particularly sea surface temperature anomaly patterns this year, large uncertainties were noted in models outputs. Continuous monitoring and updates of the regional climate situation will be made on a regular basis, especially over zone 1 (see diagram) as this is the area with the highest risk of above average number of extreme rainfall events that may lead to floods.
>> See the Outlook