Frontal Systems ChangesWeather conditions change with the passage of warm or cold fronts....

Frontal Systems Changes

Weather conditions change with the passage of warm or cold fronts. These changes are related to changes in air pressure, air temperature, and the state of water. Examine Figure 15.11 and answer the questions below which are related to key concepts from Chapter 14.

1. Describe the change in the state of water associated with the passage of a warm front.

---

2. Will this change in state cause latent heat to be released or absorbed? Justify your answer.

---

3. Describe the adiabatic temperature changes associated with the passage of a warm front.

Figure 15.11 Weather conditions associated with cross section AB on Figure 15.10. Warm air (mT) lies between the cold front and the warm front. (Left) The cold front advances more rapidly than the warm front, forcing warm air to rise and forming thunderclouds and heavy rains. (Right) Warm air is forced to rise above the more gently sloping warm front, resulting in the formation of a series of low to high clouds.

Figure 15.10 A frontal system. These are the weather patterns typically encountered with cold and warm fronts associated with a midlatitude cyclone over the central United States. Warm maritime tropical air from the Gulf of Mexico lies between the two fronts. Note that cloud cover occurs in advance of the cold front, adjacent to the warm front, and around the occluded front. Lines AB and CD represent sections through the frontal system (see Figures 15.11 and 15.13). On weather maps, a cold front is represented by a line with triangles (blue) and a warm front has semicircles (red). Both types of symbols “point” in the direction of air movement.

Figure 15.13 An occluded front. When a cold air mass overtakes a warmer air mass, an occluded front forms. Nimbostratus clouds generate precipitation along an occluded front (see section CD in Figure 15.10).