Mountain waves over Colorado

June 22nd, 2009 |
MODIS 6.7 µm and GOES-12 6.5 µm water vapor images

MODIS 6.7 µm and GOES-12 6.5 µm water vapor images

Moderate southwesterly flow aloft over the Rocky Mountains was aiding in the formation of mountain waves across much of Colorado and parts of the adjacent states on 22 June 2009. AWIPS comparisons of the 1-km resolution MODIS 6.7 µm water vapor image with the corresponding 4-km resolution GOES-12 6.5 µm water vapor image (above) and the 8-km resolution GOES-11 6.7 µm water vapor image (below) demonstrated the value of better spatial resolution for detecting such mesoscale features.

MODIS 6.7 µm and GOES-11 8-km 6.7 µm water vapor images

MODIS 6.7 µm and GOES-11 6.7 µm water vapor images

The appearance of these banded “mountain wave signatures” on water vapor imagery indicates the potential for clear air turbulence in those areas; however, there were no pilot reports of turbulence until 13:02 UTC near Fort Collins (at an altitude of 15,000 feet). An animation of the GOES-12 6.5 µm water vapor imagery (below) also showed the presence of a lee-side cold frontal gravity wave, which could be seen propagating southward across eastern Colorado and western Kansas. In fact, a small packet of waves could be seen along and behind the leading edge of this lee-side cold frontal gravity wave on the MODIS water vapor images above — surface winds behind this front had gusted to 36 knots at McCook, Nebraska (station identifier KMCK) and 20 knots at Goodland, Kansas (station identifier KGLD).

GOES-12 6.5 µm water vapor images

GOES-12 6.5 µm water vapor images

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