Development of Cold Front
The cooler and denser air wedges under the less-dense warmer air, lifting it. This upward motion causes lowered pressure along the cold front and can cause the formation of a narrow line of showers and thunderstorms when enough moisture is present. 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. A cold front's location is at the leading edge of the temperature drop off, which in an isotherm analysis would show up as the leading edge of the isotherm gradient, and it normally lies within a sharp surface trough. Cold fronts move faster than warm fronts and can produce sharper changes in weather. Since cold air is denser than warm air, it rapidly replaces the warm air preceding the boundary.
In the northern hemisphere, a cold front usually causes a shift of wind from southwest to northwest clockwise, also known as veering, and in the southern hemisphere a shift from northeast to southwest, in a clockwise manner. Normally, cold fronts can be marked by these characteristics:
| Weather phenomenon | Prior to the Passing of the Front | While the Front is Passing | After the Passing of the Front |
|---|---|---|---|
| Temperature | Warm | Cooling suddenly | Steadily cooling |
| Atmospheric pressure | Decreasing steadily | Lowest, then sudden increase | Increasing steadily |
| Winds |
|
Gusty; shifting |
|
| Precipitation/conditions* | Light patchy rain can be produced by stratocumulus or stratus in the warm sector. | Prolonged rain (nimbostratus) or thunderstorms (cumulonimbus): depends on conditions. | Showers, then clearing |
| Clouds* | Usually takes the form of a line of cumulonimbus and/or cumulus congestus clouds, but can also be nimbostratus or stratus/stratocumulus if the front is weak. Approach often obscured by stratocumulus or stratus in the warmer air approaching it, but if the air is clear usually a small sharply edged altostratus sheet can be seen marking the edge of the approaching front. | Cumulonimbus or nimbostratus | Patchy altocumulus and altostratus along with stratus fractus then cumulus and cumulonimbus |
| Visibility* | Fair to poor in haze | Poor, but improving | Good, except in showers |
| Dew Point | High; steady | Sudden drop | Falling |
*Provided there is sufficient moisture.
Read more about this topic: Cold Front
Famous quotes containing the words development of, development, cold and/or front:
“They [women] can use their abilities to support each other, even as they develop more effective and appropriate ways of dealing with power.... Women do not need to diminish other women ... [they] need the power to advance their own development, but they do not “need” the power to limit the development of others.”
—Jean Baker Miller (20th century)
“Dissonance between family and school, therefore, is not only inevitable in a changing society; it also helps to make children more malleable and responsive to a changing world. By the same token, one could say that absolute homogeneity between family and school would reflect a static, authoritarian society and discourage creative, adaptive development in children.”
—Sara Lawrence Lightfoot (20th century)
“In the cold of Europe, under prudish northern fogs, except when slaughter is afoot, you only glimpse the crawling cruelty of your fellow men. But their rottenness rises to the surface as soon as they are tickled by the hideous fevers of the tropics.”
—Louis-Ferdinand Céline (1894–1961)
“To hell with reality! I want to die in music, not in reason or in prose. People don’t deserve the restraint we show by not going into delirium in front of them. To hell with them!”
—Louis-Ferdinand Céline (1894–1961)