The Glass Ceiling: Analysis of 19 July 2006 Western Iowa Null Severe Weather Event

On July 19 th , 2006 strong near-surface warm moisture convergence over western Iowa to the southwest of an intensifying warm front boosted temperatures above 90F with dewpoints as high as 85F in some locations. Meanwhile, a very dry, generally well-mixed air mass was in place aloft. The combination of these two ingredients resulted in extreme levels of instability that, coupled with a nearly idealized wind profile and strong frontogenetical forcing, produced conditions ripe for a severe weather outbreak. However, strong warm air advection associated with the southwesterly low-level jet just above the moist boundary layer acted to intensify and deepen the capping inversion, inhibiting convective initiation. Analysis of the effects of evapotranspiration from crops is also performed.