Mountain waves downwind of the Sierra Nevada Range in California
GOES-15 6.5 µm water vapor channel images (click image to play animation)
McIDAS images of 4-km resolution GOES-15 6.5 µm “water vapor channel” data (above; click image to play animation) showed the development of a series of well-defined mountain waves immediately downwind of the high terrain of the Sierra Nevada mountains in California on 08 November 2012. This mountain wave signature indicates the potential for turbulence — and there were a few pilot reports of light to moderate turbulence in that region between the altitudes of 25,000 and 38,000 feet above ground level (17:02 UTC, 01:00 UTC).
Occasionally the crests of these mountain waves are marked by “rotor clouds” — but they also frequently occur in clear air, which underscores the importance of using water vapor imagery for their detection. AWIPS images of 1-km resolution MODIS 6.7 µm water vapor channel, 0.65 µm visible channel. and 11.0 µm IR channel data at 20:32 UTC (below) showed that there were no cloud features present with some of the mountain waves (or with the entire portion of any given mountain wave).
MODIS 6.5 µm water vapor channel, 6.5 µm visible channel. and 11.0 µm IR channel images