Ferrel cell, model of the mid-latitude segment of Earth’s wind circulation, proposed by William Ferrel (1856). In the Ferrel cell, air flows poleward and eastward near the surface and equatorward and westward at higher altitudes; this movement is the reverse of the airflow in the Hadley cell. Ferrel’s model was the first to account for the westerly winds between latitudes 35° and 60° in both hemispheres. The Ferrel cell, however, is still not a good representation of reality because it requires that the upper-level mid-latitude winds flow westward; actually the eastward-flowing surface winds become stronger with height and reach their maximum velocities around the 10-km (6-mile) level in the jet streams.