AWOS stations exist at airports in Alamosa and Trinidad (east of the Sangre de Cristo mountains), and at high points on Wolf Creek, Monarch and La Veta Passes (west, north and east of Alamosa, respectively). All three passes are commonly used by aircraft crossing the southern Rockies and are the sites of numerous aircraft crashes in which severe/extreme turbulence, windshear, downdrafts and rotors are factors.
This paper will focus upon surface pressure and wind data gathered from the five AWOSs at times typical of pilot morning weather briefings. Those data will be correlated with aviation winds aloft forecasts for the same periods. Very early results reveal anomalous winds and surface pressures (as corrected to sea level) reported from the mountain passes.
For example:
Date and Time: 10-31-2001, 0800
Place; Winds (Kn); Pressure; Height msl
Wolf Creek Pass; W 24G36; 30.22; 11,760
Alamosa; S 20G25; 30.07; 7,535
La Veta Pass; SW 25G35; 30.19; 10,216
Trinidad; SW 13; 29.93; 5,762
Monarch Pass; W 41G47; 30.22; 12,030
(Alamosa winds/temps aloft forecast for 12,000 feet: 250o at 30 kn. +01; 18,000 feet: 250o at 62 kn. -13)
The paper will concentrate on La Veta Pass and will include aircrash data, in-flight photos of that pass, and will describe safe flight routes over La Veta Pass under various wind regimes. Further research is needed relative to topography and pass high winds and pressures. Pilots must be educated as to the implications of these very important AWOS reports.
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