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.
Read more about Cold Front: Development of Cold Front, Precipitation, Temperature Changes, Characteristics of Boundaries Around An Extratropical Cyclone
Famous quotes containing the words cold and/or front:
““Are you cold too, poor Pleiads,
This frosty night?”
“Yes, and so are the Hyads:
See us cuddle and hug,” says the Pleiads,
“All six in a ring: it keeps us warm:
We huddle together like birds in a storm:”
—Robert Graves (1895–1985)
“In front of these sinister facts, the first lesson of history is the good of evil. Good is a good doctor, but Bad is sometimes a better.”
—Ralph Waldo Emerson (1803–1882)