A large area of 4-8 inches of rain fell from northwestern Oklahoma into central and eastern Kansas during the 2-day period from 30 October through 1 November.  Locally up to 11 inches of rain fell in south-central Kansas.  Numerous incidents of flash flooding closed roads and resulted in one automobile-related fatality.  Four main stem rivers in Kansas experienced record flooding: the Arkansas, the Cottonwood, the Walnut, and the Whitewater.

    Large amounts of moisture from the Gulf of Mexico focused along and north of a warm front which took the form of an inverted low-level trough.  In addition to the low level lift along this boundary, an area of upper level divergence associated with a strong system over the Southwest U.S. was moving over the Kansas/Oklahoma area.  This helped support a large area of precipitation.  Isentropic diagnoses also showed moderately strong low level lift and moisture transport, especially just north of the surface boundary.

Individual echo movement was generally to the northeast parallel to the surface boundary.  This increased the accumulation along the southwest-to-northeast axis of movement early in the period.

    With time the steering flow along became more southerly as the strong upper-level system approached from the west.  In addition, the atmosphere became more unstable with the approach of the upper system.  A line of strong echoes stretched from Kansas to north Texas.  The southern part of that line made fairly steady progress eastward, while to the north in Kansas, moderate to strong convection was slow to move.

 

    Radar provided very reasonable guidance, but there was some range degradation in the total accumulation field.  Although there was strong convection, there was also a considerable amount of general rain generated in the low levels, below the radar beam.

Rainfall intensities were not as great as other Plains cases we looked at, but the duration was greater and over a larger area.