This is certainly the driest area in the Sahel with mean precipitation in August less than 2mm/day. The 20th century time series show that the Sahel has been drying since about the late 1960s. The eastern Sahel is no exception from its neighbours as there is very little agreement among models in projecting likely precipitation trends in the 21st century and beyond. Even in this case the GFDL CM2.0 and CFDL CM2.1, and MIUB ECHO-G model projections of future precipitation diverge. It is therefore quite uncertain from the model projections considered if the eastern Sahel will continue to dry up or will experience a reversal of the late 20th century precipitation trend.
The models are clearly unable to simulate the observed 20th century annual cycle. In most of the model simulations, the observed annual cycle is much longer than in the reality, and the amplitude of the annual cycle much higher. The models do show a likelihood for the rainfall amounts to change, but the reliability of these projected changes is questionable since in some cases a reduction in precipitation is predicted in already dry months.