The JET2000 experiment took place during the last week of August 2000. Four flights with the UK Met Research Flight C-130 were made with dropsondes, involving transects across the African easterly jet and baroclinic zone. The aim of the project was to make observations of the African easterly jet and easterly waves at unprecedented resolution. It turns out that the JET2000 experiment took place during a notable dry spell in the Sahel. ECMWF analyses will be combined with satellite, radiosonde and raingauge data to illustrate the nature of the dry spell and its relationship to the African easterly jet and easterly waves. The consequences of this for seasonal prediction of rainfall will be briefly discussed.