Regional-scale flows in mountainous terrain. Part II: simplified numerical experiments

Abstract

The westward-propagating disturbance develops over a range of low-level ambient wind speed, direction, and shear but is suppressed with low-level westerly flow, which also weakens the development of its progenitor, the Front Range mountain-plains solenoid. Low-level stratification affects the depth and strength of the Front Range mountain-plains solenoid, which is most energetic in summertime conditions of near-neutral stability below 50 kPa. High stability in the lower troposphere suppresses the vertical development of the solenoid but increases the baroclinicity across the Front Range generated by surface heating, thereby still producing a significant density-current disturbance. Wet soil over the high terrain west of the Front Range also suppresses the formation and strength of the Front Range solenoid, while wet soil along the eastern slope of the Front Range and eastern plains with drier conditions over the high mountain terrain greatly enhances the baroclinicity within the solenoid and the subsequent density-current evolution. This couplet acts as an efficient conveyor of low-level moisture into the mountain region. -from Authors