On 6-7 May 2000, thunderstorms produced heavy rainfall and historic flash flooding in east-central Missouri with up to 14 inches of rain in some areas. The mesoscale convective system responsible for this heavy precipitation lacked the defined surface boundary of typical flash flood events. Rather, substantial moisture advected by a strong low-level jet contributed to the high rainfall rates.

We present here numerical simulations from the MM5-PLACE atmosphere/land-surface modeling system of the 6-7 May 2000 Missouri event. Mesoscale simulations including a sophisticated soil-vegetation model (PLACE) show marked improvement in timing and location of heavy precipitation over the default MM5 slab surface model. In addition, an important hypothesis on the interaction of soil moisture and low-level jets will be tested for this event. Dry soil conditions may disrupt the low-level jet and thus reduce moisture transport. Sensitivity tests of initial soil moisture distribution and its influence on the strength of the low-level jet and subsequent rainfall rates will be presented.