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This loop of GOES-8 visible imagery shows two elongated swaths of wet ground (darker bands oriented NW-SE) across parts of Iowa, Illinois, and Indiana on 02 June 1998. These swaths were created by precipitation from convection that propagated southeastward across that region earlier in the day.
Hourly surface reports of air temperature are plotted on the images. Although cold air advection was overspreading the region from the north and west, it appears that some of the stations located on or very near the wet ground (especially in eastern Iowa) did not warm as rapidly as those stations located over dry ground.