Cold Front (P.247)
The discontinuity at the forward edge of an advancing cold air mass that is displacing warmer air in its path.
Cold-Type Occluded Front (P.248)
A front that forms when the air behind the cold front is colder than the air underlying the warm front it is overtaking.
Conveyor Belt Model (p.268)
The modern view of cyclogenesis that provides a good picture of the airflow within a cyclonic system.
The process that creates or develops a new cyclone; also the process that produces an intensification of a preexisting cyclone.
A narrow zone in the atmosphere along which there is an abrupt change in moisture as when dry continental tropical air converges with humid maritime tropical air. The denser cT air acts to lift the less dense mT air producing clouds and storms.
A boundary (discontinuity) separating air masses of different densities, one warmer and often higher in moisture content than the other.
Middle-Latitude (Mid-latitude) Cyclone (P.243)
Large low-pressure center with diameter often exceeding 1000 kilometers that moves from west to east and may last from a few days to more than a week and usually has a cold front and a warm front extending from the central area of low pressure.
Norwegian cyclone model (P.243)
Middle-latitude cyclones develop in conjunction with the polar front.
Occluded Front (P.248)
A front formed when a cold front overtakes a warm front.
The overtaking of one front by another.
Warm air gliding up a retreating cold air mass.
Polar Front Theory (P.243)
A theory developed by J. Bjerknes and other Scandinavian meteorologists in which the polar front, separating polar and tropical air masses, gives rise to cyclonic disturbances that intensify and move along the front and pass through a succession of stages.
Speed Divergence (P.255)
The divergence of air aloft that results from the variations in velocity occurring along the axis of a jet stream. On passing from a zone of lower wind speed to one of faster speed, air accelerates and therefore experiences divergence.
Stationary Front (P.248)
A situation in which the surface position of a front does not move; the flow on either side of such a boundary is nearly parallel to the position of the front.
Warm Front (P.245)
The discontinuity at the forward edge of an advancing warm air mass that is displacing cooler air in its path.
Warm-Type Occluded Front (P.249)
A front that forms when the air behind the cold front is warmer than the air underlying the warm front it is overtaking.