Cap-
A region of negative buoyancy below an existing level of free convection (LFC) where energy must be supplied to the parcel to maintain its ascent.
Capping inversion-
A statically stable layer at the top of the atmospheric boundary layer.
Canyon wind-
The mountain wind of a canyon, that is, the nighttime down-canyon flow of air caused by cooling at the canyon walls.
Cavity-
A region of reverse flow immediately downwind of an obstacle or mountain, typically found when the static stability of the air is near neutral.
Cell-
In radar usage, a local maximum in radar reflectivity that undergoes a life cycle of growth and decay.
Central dense overcast-
The region of dense cloud near the core of a tropical cyclone.
Chergui wind-
An east or southeast desert wind in Morocco (North Africa), especially in the north.
Chinook wind-
The name given to the foehn in western North America, especially on the plains to the lee or eastern side of the Rocky Mountains in the United States and Canada.
Cloudburst-
In popular terminology, any sudden and heavy fall of rain, almost always of the shower type.
Coalescence-
In cloud physics, the merging of two water drops into a single larger drop after collision.
Conditional instability-
The state of a layer of unsaturated air when its lapse rate of temperature is less than the dry-adiabatic lapse rate but greater than the moist-adiabatic lapse rate.
Conduction-
Transport of energy (charge) solely as a consequence of random motions of individual molecules (ions, electrons) not moving together in coherent groups.
Confluence-
The rate at which adjacent flow is converging along an axis oriented normal to the flow at the point in question.
Cold front-
Any nonoccluded front, or portion thereof, that moves so that the colder air replaces the warmer air; that is, the leading edge of a relatively cold air mass.
Convection-
In general, mass motions within a fluid resulting in transport and mixing of the properties of that fluid. Convection, along with conduction and radiation, is a principal means of energy transfer.
Constant absolute vorticity trajectory-
The path of an air parcel with absolute vorticity that remains constant in horizontal flow.
Constant flux layer-
A layer of air tens of meters thick at the bottom of the atmosphere where the variation of vertical turbulent flux with altitude is less than 10% of its magnitude.
Continental aerosol-
Aerosol having its origin over the continents with industrial, urban, agricultural, forest, and desert sources, with potential for high concentrations of hygroscopic aerosol.
Convective available potential energy-
The maximum energy available to an ascending parcel, according to parcel theory.
Convection cell-
An organized unit of convection within a convecting layer. It is isolated by a stream surface, with ascending motion in the center and descending motion near the periphery, or vice versa.
Convective condensation level-
On a thermodynamic diagram, the point of intersection of a sounding curve (representing the vertical distribution of temperature in an atmospheric column) with the saturation mixing ratio line corresponding to the average mixing ratio in the surface layer.
Convective inhibition-
The energy needed to lift an air parcel vertically and pseudoadiabatically from its originating level to its level of free convection (LFC).
Convective instability-
An instability due to the buoyancy force of heavy fluid over light fluid overcoming the stabilizing influence of viscous forces.
Convective mass flux-
An average vertical transport of mass for a field of cumulus clouds or thermals.
Convective plume-
A buoyant jet in which the buoyancy is supplied steadily from a point source; the buoyant region is continuous.
Convective transport theory-
A relationship between surface fluxes and state of the air in the mid mixed layer, which applies to situations where convective thermals are causing nonlocal transport vertically in the atmospheric boundary layer.
Cut off low-
A cold low that has grown out of a trough and become displaced out of the basic westerly current and lies equatorward of this current.
