May 7, 2002 12Z

The 500 mb charts shows geostrophic winds. The low can be expected to be east of the trough at the surface.

May 7, 2002 22Z

The surface analysis shows a low pressure system. This low corresponds to the eastern portion of the trough on the 500 mb chart.

May 8, 2002 00Z

The sounding for Topeka, Kansas shows large values of CINH and small values of CAPE. The hodograph shows that the winds are veering. The 3 km helicity values are high enough to be favorable for supercells.

May 7, 2002 2235Z

Two thunderstorms are located in the Kansas area. The right storm is more intense than the other.