The Moisture Route of Palo Duro Canyon

Due to the significant discontinuity in elevation created by the Caprock Escarpment in west Texas, low-level moisture returning to that region under the influence of southeasterly flow potentially has significant interaction with that feature. The shape of the escarpment in the central Texas panhandle is such that air confined to the lowest levels would be routed into and accelerated by the increasingly narrow cross-section of Palo Duro Canyon. Eventually, the air would reach the head of the canyon and lift over the escarpment, spreading onto the tabletop plains. Though the influence of the caprock on convective initiation is something that has been pondered by storm chasers for decades, the problem is in need of further investigation for a wider variety of meteorological reasons.

To determine how the canyon influences moisture return in the real atmosphere, a vehicle-mounted mobile mesonet was employed. Through a series of traverses across the canyon, measured parameters such as temperature, dewpoint, and wind speed and direction from inside the canyon were compared to those same parameters measured in other locations outside the canyon. Data were collected for two meteorologically distinct cases, one of homogeneous return flow from the southeast, and one of a retreating dryline.

The presentation and extended abstract for this work will highlight preliminary results from both cases, which show that very coherent moisture patterns do become established relative to the canyon. In the case of the retreating dryline, dewpoint values inside the canyon were as much as 5-8ºC higher than points on the canyon rim and on the adjacent rim plains. Hypotheses for the causes of the measured trends will be presented, along with possible effects on meteorological processes such as convective initiation.