This loop of hourly GOES-8 sounder 7.0 micrometer IR ("water vapor") imagery shows the thin elongated "band" signature of a mid-tropospheric gravity wave associated with a surface cold front moving south-southwestward across New Mexico and Texas on 07 April 2000. The surface winds shift to northeasterly (and wind speeds increase to 25-30 knots) as the cold front passes, and the propagation of the warm/dry band coincides with that of the surface cold front.

This gravity wave is also evident on a loop of the GOES-8 sounder 6.5 micrometer water vapor channel, but is difficult to detect on the sounder 7.5 micrometer water vapor channel. According to the weighting functions for the 3 GOES sounder water vapor channels, the radiation sensed on the 7.0 and 6.5 micrometer channels is from layers within the middle to upper troposphere, while the 7.5 micrometer channel senses radiation predominantly from a lower layer.