| A | B |
|---|
| Cold front | the leading edge of a cooler and drier mass of air |
| conveyor belt model | a modern view of cyclogenesis |
| Dryline | a narrow zone in the atmosphere along which there is an abrupt change in moisture |
| extra tropical cyclone | outside the tropics or a middle level cyclone |
| Front | is a boundary separating two masses of air of different densities |
| Mid-latitude cyclone | group of cyclones that occur in the middle latitudes and have neither tropical nor polar characteristics |
| Norwegian cyclone model | The older of the models of extratropical cyclone development |
| Occluded front | is formed during the process of cyclogenesis when a cold front overtakes a warm front |
| Occlusion | the complex frontal structure formed when a cold front overtakes a warm front |
| Over running | warm air gliding up a retreating cold air mass |
| Polar front | a theory in which the polar front separates polar and tropical fronts gives rise to cyclones |
| Speed divergence | the divergence of air aloft that results from the variations in velocity along the jet stream |
| Stationary front | is a boundary between two different air masses, neither of which is strong enough to replace the other |
| Warm front | the leading edge of an advancing mass of warm air; it separates warm air from the colder air ahead |
| cyclone | an area of low atmospheric pressure characterized by inward spiralling winds that rotates |
| vorticity | the amount of "circulation" or "rotation" in a fluid |
| blocks | large scale patterns in the atmospheric pressure field that are nearly stationary |
| Cyclogenesis | the development or strengthening of cyclonic circulation in the atmosphere |
