MISSOURI CONVECTIVE DEVELOPMENT
. . . . . The new Missouri convective activity developed about 30 km east of the Pleasant Hill NWS office, but it immediately began moving off toward the north-northeast at 35-40 kt. Within a short time, the activity had moved beyond the 100 km optimal range, just as a complex evolution began. This evolution included:
1) the northernmost storm ("N" in figure) intensified quite dramatically into a supercell with mesocyclone by 2241 UTC,
2) the 'middle' storm (M) moved up between its two neighbors and began to weaken,
3) and the southernmost storm (S) grew relatively slowly with time.
An animated loop of the radar reflectivity can be viewed using an MPEG viewer. At the range of the three storms from both the EAX and STL radars (STL illustrated in figure and loop), the lowest elevation angle would have been viewing these storms between 8,000 to 10,000 ft. Thus, both radar beams were entirely above the boundary layer, and could not 'see' any important outflow interactions occuring at lower levels. The only way for an alert radar operator to know what was occurring at that point was by implication. That is, the center cell can be seen to move up between its two neighbors. As it does so, it weakens appreciably -- implying a burst of heavy rain, and (presumably) new outflow.