The first map indicates the total rainfall amount from 1^st to 20^th July. Data is extracted from FAO field reports and the RainFall Estimate (RFE) satellite imagery as produced by NOAA/USGS/FEWS/USAID project. The RFE images are obtained by interpolating various parameters recorded on the ground and obtained through remote sensing measurements such as: rainfall, relative humidity, wind speed, elevation, cold cloud temperatures.

The map below shows the forecast yield of cereals (maize, millet, sorghum) for the Sahelian countries for the 1999 cropping season, as percent of the average yield of last five years (1993-98). The map is obtained by applying to each country a yield function which relates, in a statistical way for the period 1982-98, the output parameters from the FAO crop specific water balance model to the crop yield. For 1999, the water balance model is using average rainfall from 21^st July to the end of the crop cycle.