Movement and Fronts
A weather front is a boundary separating two masses of air of different densities, and is the principal cause of meteorological phenomena. In surface weather analyses, fronts are depicted using various colored lines and symbols, depending on the type of front. The air masses separated by a front usually differ in temperature and humidity. Cold fronts may feature narrow bands of thunderstorms and severe weather, and may on occasion be preceded by squall lines or dry lines. Warm fronts are usually preceded by stratiform precipitation and fog. The weather usually clears quickly after a front's passage. Some fronts produce no precipitation and little cloudiness, although there is invariably a wind shift.
Cold fronts and occluded fronts generally move from west to east, while warm fronts move poleward. Because of the greater density of air in their wake, cold fronts and cold occlusions move faster than warm fronts and warm occlusions. Mountains and warm bodies of water can slow the movement of fronts. When a front becomes stationary, and the density contrast across the frontal boundary vanishes, the front can degenerate into a line which separates regions of differing wind velocity, known as a shearline. This is most common over the open ocean.
Read more about this topic: Air Mass
Famous quotes containing the words movement and, movement and/or fronts:
“An actor rides in a bus or railroad train; he sees a movement and applies it to a new role. A woman in agony of spirit might turn her head just so; a man in deep humiliation probably would wring his hands in such a way. From straws like these, drawn from completely different sources, the fabric of a character may be built. The whole garment in which the actor hides himself is made of small externals of observation fitted to his conception of a role.”
—Eleanor Robson Belmont (1878–1979)
“The writer may very well serve a movement of history as its mouthpiece, but he cannot of course create it.”
—Karl Marx (1818–1883)
“As Jerome expanded, its chances for the title, “the toughest little town in the West,” increased and when it was incorporated in 1899 the citizens were able to support the claim by pointing to the number of thick stone shutters on the fronts of all saloons, gambling halls, and other places of business for protection against gunfire.”
—Administration in the State of Ariz, U.S. public relief program (1935-1943)