This view was obtained by the NOAA-12 satellite on 1997 May 18 23:14 UT (6:14 PM CDT). It is a color composite made by combining AVHRR channels 1, 2, and 4 as red, green, and blue. Channel 4 was reversed to make cold brighter so the high clouds would appear more white.
The large storm complex had tornados and golf ball size hail near Chicago on the afternoon of Sunday, May 18, 1997. In the large view the top of this storm shows numerous details in the low evening sunlight. A map of the satellite pass shows the sun to be at about 20 degrees above the western horizon for the large storm. The small circular storm is near the edge of the scan so is not imaged as sharply.
Measurements may be made on the image. The large storm complex extends about 260 miles in its longest dimension. The small circular storm is about 37 miles in diameter, and its shadow is clearly visible on the ground below. From the map of the pass the sun's altitude at this storm's position can be estimated to be about 23 degrees. The shadow was measured to extend about 150,000 feet beyond the edge of the storm, so this edge is about 65,000 feet above the surface.
