During the ER-2 flight on this day, there were clear sky conditions west of the ARM CART site. Low level cloud was over the ARM site until about 2000 UTC when it began to clear out. The following HIS spectra is an average of 9 observations made between 1913-1914 UTC when the ER-2 was west of the ARM site. The hot brightness temperatures are consistent with the GOES-8 11 micron imager.