Which type of front is associated with a sharp drop in baro-metric pressure? Thinking back to what you learned about precipitation in Chapter 6, which type of front favors the formation of freezing rain in winter?
Ch7 Lab – Fronts and Violent Weather
Cold front and squall line. A sharp line of cumulonimbus clouds near the Texas coast and Gulf of Mexico marks the squall line and front. The clouds rise to 17,000 m (56,000 ft). [NASA.]
Chapter 7 Weather 191
Warm air masses can be carried by the jet stream into regions with colder air, such as when an atmos-pheric river of water vapor called the “Pineapple Ex-press” carries warm, moist air from Hawai’i and the Pacific into California. Warm air also advances dur-ing monsoonal flow conditions, such as when mT air moves from the Pacific Ocean into the low-pressure areas over the heated landmasses of the U.S. Southwest during July and August. At times, two air masses may meet and form a stationary front, one that remains in place for an extended period. Along a stationary front, airflow on either side is almost parallel to the front, although in opposite directions, and gentle lifting might produce light to moderate precipitation. Eventually, the station-ary front will begin to move, as one of the air masses assumes dominance, evolving into a warm or a cold front.
Using the text description and Figures 7.8 and 7.10, answer the following questions.
1. Which type of front is associated with a sharp drop in baro-metric pressure?
2. Thinking back to what you learned about precipitation in Chapter 6, which type of front favors the formation of freezing rain in winter?
3. What two characteristics of a cold front produce more se-vere weather than is associated with a warm front?
Note the sequence of cloud development as the warm front approaches. Warm air upward over a wedge of cooler, passive air near the ground. Gentle lifting of the warm, moist air produces clouds and iFiguy„ ly rain showers.
