This loop of hourly GOES-8 6.7 micrometer IR ("water vapor") imagery shows the warming/drying trend across Minnesota and Wisconsin, indicating synoptic-scale subsidence in the wake of a short wave trough moving through the Great Lakes region.

Note the convection early in the loop over northern Wisconsin, and then later in the loop over eastern Iowa and northern Illinois. This convection may have acted to vertically re-distribute some of the elevated smoke layer that was seen over the region late in the day on 08 August, forming thin layers at somewhat lower altitudes that were then detected by regional WSR-88D radars on 09 August.