Region of convergence, often a line, downwind of a mountain or mountain ridge during fair-weather daytime conditions that are favorable for the formation of thermally forced upslope flow and deep conv
ective mixing. Convergence forms between upslope (or sometimes light and variable) flow at lower elevations of the lee slopes and downslope flow at higher elevations, which results from the downward convective mixing of ambient momentum from the flow above ridgetops. With moist upslope flow and favorable conditions, updrafts produced by the convergence can lead to mountain cumulus formation, or trigger thunderstorm or severe weather activity.
1. Any wave disturbance that is caused by, and is therefore stationary with respect to, some barrier in the fluid flow. Whether the wave is a gravity wave, inertia wave, barotropic wave, etc., will de
pend on the structure of the fluid and the dimensions of the barrier. 2. A mountain wave occurring to the lee of a mountain or mountain barrier. These waves can become visible in the form of lenticular or trapped lee-wave clouds.