Frontal+Systems

DEF:
 * Warm Front **

A warm front is defined as the transition zone where a warm air mass is replacing a cold air mass.

MOVEMENT`:

Warm fronts generally move from southwest to northeast.

INFO:

The air behind a warm front is warmer and more moist than the air ahead of it. When a warm front passes through, the air becomes noticeably warmer and more humid than it was before. If warmer air is replacing colder air, then the front should analyzed as a warm front.

SYMBOL:

Symbolically, a warm front is represented by a solid line with semicircles pointing towards the colder air and in the direction of movement. On colored weather maps, a warm front is drawn with a solid red line.

** Occluded Front ** DEF:

When a cold front overtakes a warm front.

HOW IT FORMS:

A developing cyclone typically has a preceding warm front and a faster moving cold front. North of the warm front is a mass of cooler air that was in place before the storm even entered the region. As the storm intensifies, the cold front rotates around the storm and catches the warm front. This forms an occluded front, which is the boundary that separates the new cold air mass from the older cool air mass already in place north of the warm front. Changes in temperature, dew point temperature, and wind direction can occur with the passage of an occluded front. A noticeable wind shift also occurred across the occluded front. East of the front, winds were reported from the east-southeast while behind the front, winds were from the west-southwest. Common characteristics associated with occluded fronts have been listed in the table below.

SYMBOL:

Symbolically, an occluded front is represented by a solid line with alternating triangles and circles pointing the direction the front is moving. On colored weather maps, an occluded front is drawn with a solid purple line. ** Cold Front ** DEF: A cold front is defined as the transition zone where a cold air mass is replacing a warmer air mass.

MOVEMENT:

Cold fronts generally move from northwest to southeast.

INFO:

The air behind a cold front is noticeably colder and drier than the air ahead of it. When a cold front passes through, temperatures can drop more than 15 degrees within the first hour. There is typically a noticeable temperature change from one side of a cold front to the other. An abrupt temperature change over a short distance is a good indicator that a front is located somewhere in between. If colder air is replacing warmer air, then the front should be analyzed as a cold front. On the other hand, if warmer air is replacing cold air, then the front should be analyzed as a warm front.

SYMBOL

Symbolically, a cold front is represented by a solid line with triangles along the front pointing towards the warmer air and in the direction of movement. On colored weather maps, a cold front is drawn with a solid blue line. ** Stationary Front  ** DEF:

When a warm or cold front stops moving, it becomes a stationary front.

INFO: Once this boundary resumes its forward motion, it once again becomes a warm front or cold front. A noticeable temperature change and/or shift in wind direction is commonly observed when crossing from one side of a stationary front to the other. SYMBOL:

A stationary front is represented by alternating blue and red lines with blue triangles pointing towards the warmer air and red semicircles pointing towards the colder air. WORK CITED:

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