| A | B |
|---|
| zones of convergence | region of low pressure |
| zones of divergence | region of high pressure |
| air mass | large area of air within the lower atmosphere having generally the same temperature and humidity at any given level |
| source region | place on earth where an air mass forms |
| cyclone (LOW) | low pressure air mass with counterclockwise winds in the northern hemisphere, including violent weather, such as tornadoes and hurricanes. |
| anticyclone (HIGH) | the opposite of a cyclone, having high pressure and clockwise winds in the northern hemisphere |
| front | the interface between two different air masses, such as the point of contact between warm and cold air masses on the ground |
| warm front | the interface, leading edge, of an air mass which has warmer temperatures than the preceding cooler air mass |
| cold front | the interface, leading edge, of an air mass which has cooler temperatures than the preceding warmer air mass, usually associated with moisture and precipitation |
| occluded front | interface formed when a cold front overtakes a warm front |
| stationary front | interface of two air masses that do not move |
| isotherm field gradient | degree of change in temperature shown by isolines |
| frontal surface | the interface between two different air masses, such as the point of contact between warm and cold air masses in the air |
| pressure field gradient | degree of change in pressure shown by isolines; where they are closest together wind speed is greatest |
| weather forcasting | predicting weather changes based on tracking air masses |
| station model | on a weather map, describes weather conditions at a reporting station |
| synoptic weather map | broad "birds eye view" of the weather |
| storm track | path taken by the center of a storm or low pressure system |
| jet stream | wavelike currents with high winds at upper levels which tend to control storm tracks |
| meteorologist | studies, reports, and forecasts weather conditions, as on television |
| thunderstorm | transient, sometimes violent storm of thunder and lightning, often accompanied by rain and sometimes hail |
| hurricane | tropical cyclone with winds in excess of 119 km/hr (75 mph) |
| "eye" of the storm | the central area of calm in a hurricane |
| tornado | small, violent storm with a characteristic funnel-shaped cloud |
| vortex | the center of a tornadoes funnel-shaped cloud |
