Plain English Meaning
When wind blows over a mountain range, the air keeps bouncing up and down on the far side, like ripples flowing downstream from a rock in a river. These invisible waves in the air can be smooth in places and very rough in others, with powerful rising and sinking air.
Full Definition
An atmospheric wave disturbance formed when stable air flows across a mountain ridge at sufficient speed, producing a series of standing waves on the downwind side. These waves can extend for many miles downwind and reach altitudes well above the ridge, often producing strong updrafts and downdrafts, severe turbulence, and rotor circulations near the surface.
Context Anchor
Pilots encounter Mountain Wave in , , planning near , and of or strong changes downwind of mountains.