Exceptional atmospheric circulation during the "Dust Bowl"

The three-dimensional, regional and large-scale atmospheric circulation during the "Dust Bowl" is analyzed based on newly available historical upper-air data and reconstructed upper-level fields. The Great Plains Low Level Jet, transporting moisture into the region, was weakened on its eastern side, shallower, and penetrated less far north than during wet years. Nocturnal convection was likely suppressed by increased stability. Strong mid-tropospheric ridging was found over the Great Plains, and upper-tropospheric flow anomalies extended from the North Pacific across North America to the Atlantic. These findings provide a dynamical view of the "Dust Bowl" droughts, some aspects of which are distinct from other droughts. It is demonstrated that this is important for assessing predictive capabilities of current modeling Systems.