what is a cold front

what is a cold front

1 year ago 35
Nature

A cold front is a boundary between two air masses that contain different temperature, wind, and moisture properties. It is the leading edge of a cooler mass of air at ground level that replaces a warmer mass of air and lies within a pronounced surface trough of low pressure. A cold front occurs when a mass of comparatively colder air moves into where warmer air is present. The drier, colder air forms a steeply sloping boundary under the warmer, moister air at the surface and lifts that air. This often causes cloud formations with a strong vertical development, which may manifest as a line of showers and thunderstorms when enough moisture is present.

Some key features of a cold front include:

  • Temperature changes: Temperature changes associated with cold fronts can be as much as 30 °C (54 °F) . Temperature changes along the boundary of the cold/warm air can be in excess of 50° F (10° C) .

  • Wind: When cold fronts come through, there is usually a quick, yet strong gust of wind that shows that the cold front is passing. In surface weather observations, a remark known as FROPA is coded when this occurs.

  • Precipitation: The amount of precipitation associated with a cold front depends on the amount of moisture in the air and the amount of lifting the front produces. You need both abundant moisture and strong lifting to produce significant precipitation. Sometimes bands of precipitation can occur well ahead of the front, especially if the warm air mass is unstable. The cold front itself commonly brings a narrow band of precipitation that follows along the leading edge of the cold front. These bands of precipitation can be very strong and can bring severe thunderstorms, hailstorms, snow squalls, and/or tornadoes.

Cold fronts usually move from northwest to southeast. They tend to be strongest in the spring and the fall and weakest in the summer. As a cold front is passing through, temperatures drop quickly and then steadily decline as it passes. If youre watching the weather forecast on your local news, a cold front will be marked by a solid blue line.

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