Low-Level Airflow in Southern Wyoming during Wintertime

Abstract

A number of low-level flights were conducted with an instrumented aircraft to investigate wind characteristics in the planetary boundary layer over the low regions of the continental divide in southern Wyoming. The airflow upwind of the continental divide is stably-stratified and as it converses through Wyoming's ?wind corridor&rdquo, a strong horizontal thermal gradient or baroclinic zone develops. The coldest air moves through the northern part of the wind corridor and is ovelain by a very stable layer. Trapped lee waves are prevalent in the planetary boundary layer of the wind corridor. Through the corridor the forces normal to the flow an in approximate balance and the flow is an anomalous anticyclonic flow around a low. Downwind of the wind corridor the airflow forms a convergence zone on its southern boundary with air from north-central Colorado. The convergence zone appears to remain distinct for ? 100 km downwind of the Medicine Bow Mountains. The flow through smaller gaps was also investigated. Flows with hydraulic jump characteristics were observed.