cold front

leading edge of a mass of cooler air (Meteorology)

A cold front is defined as the leading edge of a cooler and drier mass of air. The air with greater density wedges under the less dense warmer air, lifting it, which can cause the formation a narrow line of showers and thunderstorms when enough moisture is present. This upward motion causes lowered pressure along the cold front. On weather maps, the surface position of the cold front is marked with the symbol of a blue line of triangles/spikes (pips) pointing in the direction of travel. Cold fronts can move up to twice as fast as warm fronts.
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A surface weather analysis is a special type of weather map which provides a view of weather elements over a geographical area at a specified time based on information from ground-based weather stations. Weather maps are created by plotting or tracing the values of relevant quantities such as sea level pressure, temperature, and cloud cover onto a geographical map to help find synoptic scale features such as weather fronts.
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Noun
1. the front of an advancing mass of colder air
(synonym) polar front
(hypernym) front
(hyponym) squall line

Synonyms and related words:
air mass, anticyclone, cold sector, cyclone, front, high, high-pressure area, isobar, isometric, isometric line, isopiestic line, isotherm, isothermal line, low, low-pressure area, occluded front, polar front, squall line, stationary front, warm front, weather map, wind-shift line,
  

FRONTE FREDDO [METEREOLOGIA]