Extended Abstract (876K)P3.35
Mountain-Wave Induced Windstorms West of Westcliffe, Colorado
Paul G. Wolyn, NOAA/NWSFO, Pueblo, CO; and T. Magnuson
Windstorms in the lee of large mountain barriers have been observed in many locations. Probably the most studied location in the United States is the Boulder, Colorado area, due to its significant population density and large number of research and operational meteorologists. There are many other lesser known areas in the lee of mountain barriers which experience similar mountain wave induced high wind events. However, these places are not well know due to sparse population.
The region just west of Westcliffe, Colorado is another location where mountain wave induced high wind events can occur. A National Weather Service Pueblo weather spotter, located about 11 km (7 miles) west of Westcliffe, Colorado, will sometimes report wind speeds in excess of 35 m/s (70 knots), while Westcliffe will report non-damaging wind speeds. An employee from the National Weather Service office in Pueblo visited the site to determine whether the reports are realistic. The spotter's wind equipment was of good quality and sited properly, therefore the high wind speeds where considered realistic. Other anecdotal evidence from the region, such a windows on the west sides of buildings being boarded over, provide further evidence of damaging winds occurring with some frequency.
The location of the high winds are immediately in the lee of the Sangre de Cristo Mountains at an elevation of around 2580 m AMSL (about 8500 feet). Around 8 km (5 miles) to the west of the site, the Sangre de Cristo Mountains crest at around 3950 m AMSL (13,000 feet). The site is at the mouth of a fairly narrow west-southwest to east-northeast trending valley. These valleys are quite common in the northern Sangre de Cristo Mountains, having been cut by ancient glaciers and drainage basins. The Sangre de Cristo Mountains are a north-northwest to south-southeast oriented barrier. This site is located in the Wet Mountain Valley with the Wet Mountains rising to over 3650 m (12,000 feet) on the east side of the valley. Several cases of high winds will be summarized. Analysis of one case indicates high winds occur with strong west-southwest flow aloft with a synoptic evolution similar to windstorms in Boulder, Colorado.
Poster Session 3, Topographic Flows (with Coffee Break)
Thursday, 20 June 2002, 2:45 PM-4:30 PM
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