Cold Front

A cold front is defined as the leading edge of a cooler mass of air, replacing (at ground level) a warmer mass of air, which lies within a fairly sharp surface trough of low pressure. It forms in the wake of an extratropical cyclone, at the leading edge of its cold air advection pattern, which is also known as the cyclone's dry conveyor belt circulation. Temperature changes across the boundary can be as much as 30 °C (54 °F). When enough moisture is present, rain can occur along the boundary. If there is significant instability along the boundary, a narrow line of thunderstorms can form along the frontal zone. If instability is less, a broad shield of rain can move in behind the front, which increases the temperature difference across the boundary. They are stronger in the fall and spring transition seasons, and weakest during the summer. When they catch up with the preceding warm front, the portion of the boundary which does so is then known as an occluded front.

Famous quotes containing the words cold and/or front:

“If the factory people outside the colleges live under the discipline of narrow means, the people inside live under almost every other kind of discipline except that of narrow means—from the fruity austerities of learning, through the iron rations of English gentlemanhood, down to the modest disadvantages of occupying cold stone buildings without central heating and having to cross two or three quadrangles to take a bath.”
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“I may be able to spot arrowheads on the desert but a refrigerator is a jungle in which I am easily lost. My wife, however, will unerringly point out that the cheese or the leftover roast is hiding right in front of my eyes. Hundreds of such experiences convince me that men and women often inhabit quite different visual worlds. These are differences which cannot be attributed to variations in visual acuity. Man and women simply have learned to use their eyes in very different ways.”
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