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Arctic front
The boundary or front separating deep, cold arctic air from shallower, relatively less cold polar air.
Back Door Cold Front
A cold front moving south or southwest along the Atlantic seaboard and Great Lakes; these are especially common during the spring months.
Cold Front
A zone separating two air masses, of which the cooler, denser mass is advancing and replacing the warmer.
Dew Point Front
A narrow zone (mesoscale feature) of extremely sharp moisture gradient and little temperature gradient. It separates moist air from dry air. Severe weather can be associated with this front. It is also known as a "dryline" or "dry front".
Front
A boundary or transition zone between two air masses of different density, and thus (usually) of different temperature. A moving front is named according to the advancing air mass, e.g., cold front if colder air is advancing.
Frontal Inversion
A temperature inversion that develops aloft when warm air overruns the cold air behind a front.
Frontogenesis
1. The initial formation of a front or frontal zone. 2. In general, an increase in the horizontal gradient of an airmass property, principally density, and the development of the accompanying features of the wind field that typify a front.
Gust Front
The leading edge of gusty surface winds from thunderstorm downdrafts; sometimes associated with a shelf cloud or roll cloud. See also gustnado or outflow boundary.
Katafront
A front where the warm air descends the frontal surface (except in the low layers of the atmosphere).
Left Front Quadrant
Used interchangably with Left Exit Region; the area downstream from and to the left of an upper-level jet max (as would be viewed looking along the direction of flow). Upward motion and severe thunderstorm potential sometimes are increased in this area relative to the wind speed maximum. See also entrance region, right rear quadrant.
Occluded Front
A composite of two fronts, formed as a cold front overtakes a warm or quasi-stationary front. Two types of occlusions can form depending on the relative coldness of the air behind the cold front to the air ahead of the warm or stationary front. A cold occlusion results when the coldest air is behind the cold front and a warm occlusion results when the coldest air is ahead of the warm front.
Polar Front
A semipermanent, semicontinuous front that separates tropical air masses from polar air masses.
Pre-Frontal Squall Line
A line of thunderstorms that precedes an advancing cold front.
Pre-Frontal Trough
An elongated area of relatively low pressure preceding a cold front that is usually associated with a shift in wind direction.
Pseudo-Cold Front
A boundary between a supercell's inflow region and the rear-flank downdraft (or RFD). It extends outward from the mesocyclone center, usually toward the south or southwest (but occasionally bows outward to the east or southeast in the case of an occluded mesocyclone), and is characterized by advancing of the downdraft air toward the inflow region. It is a particular form of gust front.
Pseudo-Warm Front
A boundary between a supercell's inflow region and the forward-flank downdraft (or FFD). It extends outward from at or near the mesocyclone center, usually toward the east or southeast, and normally is either nearly stationary or moves northward or northeastward ahead of the mesocyclone.
Quasi-stationary Front
A front which is nearly stationary or moves very little since the last synoptic position. Also known as a stationary front.
Sea Breeze Front
The leading edge of a sea breeze, whose passage is often accompanied by showers, a wind shift, or a sudden drop in temperature.
Stationary Front
A front between warm and cold air masses that is moving very slowly or not at all.
Warm Front
A transition zone between a mass of warm air and the colder air it is replacing.
Wrapping Gust Front
A gust front which wraps around a mesocyclone, cutting off the inflow of warm moist air to the mesocyclone circulation and resulting in an occluded mesocyclone.

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     Page last Modified: 25 June, 2009 1:01 PM