Vacillation-
Oscillation, usually of a small amplitude, about a reference state.
Valley wind-
A wind that ascends a mountain valley (upvalley wind) during the day; the daytime component of a mountain valley wind system.
Vapor-
Any substance existing in the gaseous state at a temperature lower than that of its critical point; that is, a gas cool enough to be liquefied if sufficient pressure were applied to it.
Vapor pressure-
The pressure exerted by the molecules of a given vapor.
Vector-
Any quantity, such as force, velocity, or acceleration, that has both magnitude and direction at each point in space, as opposed to a scalar that has magnitude only.
Veering wind-
In the Northern Hemisphere, a wind that rotates in a clockwise direction with increasing height; the opposite of backing wind.
Velocity-
The time rate of change of a position vector; that is,a change of position expressed in terms of speed and direction.
Vertical wind shear-
The condition produced by a change in wind velocity (speed and/or direction) with height.
Viscous force-
The transport of mass motion momentum solely by the random motions of individual molecules not moving together in coherent groups.
Visibility-
The greatest distance in a given direction at which it is just possible to see and identify with the unaided eye
Vortex-
More often the term refers to a flow with closed streamlines or to the idealized case in which all vorticity is concentrated in a vortex filament.
Vorticity advection-
Advection of vorticity by the total wind
