Case 1 (Forward Shear)
The forward shear between 2 and 8 km causes the Scorer parameter associated with this background flow to decrease with height. This decrease in the Scorer parameter leads to the generation of trapped mountain lee waves, which, in turn, is consistent with the predictions of linear theory. The signature of these trapped lee waves is most clearly evident in the vertical velocity field. Note the vertical orientation of the phase lines associated with the trapped lee waves. Such a phase line orientation is indicative of horizontal energy propagation. And finally, note that although the surface wind speed and mountain profile characteristics are the same for the Reference profile and Case 1, the mountain wave associated with Case 1 no longer comes any where close to breaking. In other words, the addition of forward shear acts to suppress wave breaking and the formation of a wave-induced critical level.