Recall a front is the line on a surface weather map that marks the narrow transition zone between air masses of different density (due to contrasts in temperature and/or humidity). An air mass, in turn, is a huge volume of air covering tens of thousands of square kilometers with generally horizontally uniform temperature and humidity in the horizontal. 1. Cold, dry air is warm, humid air. Consequently, lighter warmer air is forced to rise above the sloping front overlying denser colder air. a. denser than b. less dense than 2. Ascending unsaturated air , cooling at about 10C per 1000m of ascent (5.5F per 1000ft.). a. expands b. is compressed3. Warmer air rising above a front expands and cools as it ascends, and its relative humidity If saturated, clouds develop and rain or snow may fall from those clouds. a. increases b. decreases c. remains constant 4. The relative humidity of saturated air is a. 50% b. 98% c. 100% d. 105% Clouds and precipitation can develop in the ascending branch of a convection current, along a front, and up the windward slopes of a mountain range. The ascending branch of a convective current may produce an upward billowing cloud known as a cumulus cloud. For a review of cloud types and their development, see Chapter 7 of the Weather Studies textbook.5. Prevailing upper-level winds blow from west to east across the United States. Winds blowing onshore from the Pacific Ocean are forced up the windward slopes of the Cascade Mountain Range in the Pacific Northwest. Hence, the heaviest precipitation falls on the slopes of the Cascades. a. eastern b. western Precipitation generally forms from the lifting of humid air, which causes adiabatic cooling of the air and leads to condensation and cloud formation. Cloud growth can produce water droplets and/or ice particles heavy enough to fall and reach the surface as precipitation.6. Comparing Figure 7A-1 and Figure 7A-2, the precipitation in Ohio, Pennsylvania and New York advanced with the occluded and cold fronts toward the This movement was evident from the drop in air pressure for Pittsburgh, PA as well as precipitation for Buffalo, NY and Montreal, Canada. a. east b. north c. west d. south7. In Figure 7A-2, there was rainfall ahead of the cold front in Pennsylvania compared to Figure 7A1. a. less b. more 8. The air mass on the western flank of the Atlantic anticyclone and ahead of the advancing fronts in the Southeast in Figure 7A-2 was unseasonably mild. In fact, temperatures in southeast Texas and Louisiana, to the south and east of the cold front, were generally in the (F). This air mass was distinct from the air mass to the north of the cold front, where it was cooler with lower dewpoints. a. 40s b. 50s c. 60s d. 70s.

1. Recall a front is the line on a surface weather map that marks the narrow transition zone between
air masses of different density (due to contrasts in temperature and/or humidity). An air mass, in
turn, is a huge volume of air covering tens of thousands of square kilometers with generally
horizontally uniform temperature and humidity in the horizontal. 1. Cold, dry air is warm, humid air.
Consequently, lighter warmer air is forced to rise above the sloping front overlying denser colder
air. a. denser than b. less dense than 2. Ascending unsaturated air , cooling at about 10C per
1000m of ascent (5.5F per 1000ft.). a. expands b. is compressed3. Warmer air rising above a front
expands and cools as it ascends, and its relative humidity If saturated, clouds develop and rain or
snow may fall from those clouds. a. increases b. decreases c. remains constant 4. The relative
humidity of saturated air is a. 50% b. 98% c. 100% d. 105% Clouds and precipitation can develop
in the ascending branch of a convection current, along a front, and up the windward slopes of a
mountain range. The ascending branch of a convective current may produce an upward billowing
cloud known as a cumulus cloud. For a review of cloud types and their development, see Chapter
7 of the Weather Studies textbook.5. Prevailing upper-level winds blow from west to east across
the United States. Winds blowing onshore from the Pacific Ocean are forced up the windward
slopes of the Cascade Mountain Range in the Pacific Northwest. Hence, the heaviest precipitation
falls on the slopes of the Cascades. a. eastern b. western Precipitation generally forms from the
lifting of humid air, which causes adiabatic cooling of the air and leads to condensation and cloud
formation. Cloud growth can produce water droplets and/or ice particles heavy enough to fall and
reach the surface as precipitation.6. Comparing Figure 7A-1 and Figure 7A-2, the precipitation in
Ohio, Pennsylvania and New York advanced with the occluded and cold fronts toward the This
movement was evident from the drop in air pressure for Pittsburgh, PA as well as precipitation for
Buffalo, NY and Montreal, Canada. a. east b. north c. west d. south7. In Figure 7A-2, there was
rainfall ahead of the cold front in Pennsylvania compared to Figure 7A1. a. less b. more 8. The air
mass on the western flank of the Atlantic anticyclone and ahead of the advancing fronts in the
Southeast in Figure 7A-2 was unseasonably mild. In fact, temperatures in southeast Texas and
Louisiana, to the south and east of the cold front, were generally in the (F). This air mass was
distinct from the air mass to the north of the cold front, where it was cooler with lower dewpoints.
a. 40s b. 50s c. 60s d. 70s