Question 1

"Back-door" cold fronts are most common in the Pacific Northwest of the United States.

Accepted Answer

"Back-door" cold fronts are more common in the Eastern United States, particularly in the Northeast, where they move in from the east or northeast, opposite the typical west-to-east movement of weather systems in the U.S.

Question 2

In an exceptionally cold winter during which the Great Lakes were entirely covered by ice, lake effect snows would be expected in extremely high frequency and intensity.

Accepted Answer

Lake effect snow occurs when cold air moves over the warmer waters of the lakes, picking up moisture and then depositing it as snow on the downwind shores. If the Great Lakes were entirely covered by ice, this process would be significantly reduced, leading to less lake effect snow.

Question 3

Cold fronts are colored purple on a weather map.

Accepted Answer

Cold fronts are typically colored blue on weather maps, while warm fronts are colored red.

Question 4

Along the boundary between continental polar and maritime tropical air masses, widespread precipitation and storminess are often found.

Accepted Answer

This boundary, often referred to as a front, is where the cold, dry air of a continental polar air mass meets the warm, moist air of a maritime tropical air mass. The interaction between these differing air masses can lead to the development of precipitation and storms.

Question 5

The "average" speed of a cold front is about half that of an "average" warm front.

Accepted Answer

The "average" speed of a cold front is typically faster than that of a warm front. Cold fronts tend to move more rapidly due to the dense, cold air pushing and sliding underneath the warmer air ahead of it.

Question 6

Drylines may be detected by Doppler radar when insects and insect-eating birds congregate along them. On the radar screen, the echo from insects and birds shows up as a thin line, called a fine line.

Accepted Answer

Doppler radar can detect fine lines caused by insects and birds congregating along drylines, as their movement and density create echoes that appear on the radar screen.

Question 7

A good source region for an air mass would be ____.

Accepted Answer

Air masses form over generally flat areas of uniform composition with light surface winds, allowing the air to take on the characteristics of the surface below it without much disturbance.

Question 8

Freezing rain more commonly occurs with warm fronts than with cold fronts.

Accepted Answer

Freezing rain is more common with warm fronts because they involve warm air overrunning colder air near the surface, which leads to precipitation falling as rain and then freezing upon contact with cold surfaces. Cold fronts typically bring a rapid change in air mass, with cold air moving in quickly and not favoring the conditions needed for freezing rain.

Question 9

Continental arctic and continental polar air masses can be difficult to distinguish, especially when the arctic air mass has traveled over warmer terrain.

Accepted Answer

Continental arctic (cA) and continental polar (cP) air masses both originate over land in high latitude regions, making them cold and dry. However, as an arctic air mass moves over warmer terrain, it can moderate somewhat, making it more challenging to distinguish from a polar air mass based on temperature and moisture characteristics alone.

Question 10

In the Central Plains of the United States, continental polar air is welcome in both winter and summer.

Accepted Answer

In the Central Plains of the United States, continental polar air is generally welcome in the summer because it brings cooler temperatures, but in the winter, it can contribute to very cold conditions, making it less welcome.

Question 11

The origin of cP and cA air masses that enter the United States is

Accepted Answer

cP (continental Polar) air masses that affect the United States primarily originate from Northern Canada and Alaska. These air masses are characterized by cold temperatures and low moisture levels due to their continental and polar origins.

Question 12

Fronts are associated with high pressure.

Accepted Answer

Fronts are associated with low pressure systems where different air masses meet, not high pressure systems.

Question 13

At the surface, occluded fronts are always followed by colder air.

Accepted Answer

Occluded fronts occur when a cold front overtakes a warm front, which can lead to a mixture of weather patterns, and the air that follows can be warmer or colder depending on the characteristics of the colliding air masses.

Question 14

On a colored weather map, a stationary front is drawn as an alternating red and blue line. Red semicircles face toward colder air on the red line and blue triangles point toward warmer air on the blue line.

Accepted Answer

A stationary front is depicted as an alternating red and blue line, with red semicircles that face the colder air and blue triangles that point towards the warmer air, indicating the boundary where cold and warm air masses meet without significant movement.

Question 15

A good air mass source region is generally flat and of uniform composition with light surface winds.

Accepted Answer

A good air mass source region is typically flat and uniform in composition, allowing the air above it to acquire uniform temperature and moisture characteristics, and light winds facilitate this process without causing too much mixing.

Question 16

Continental tropical (cT)air masses are responsible for the heat waves of summer in the western United States.

Accepted Answer

Continental tropical (cT) air masses are hot, dry air masses that form over land in the subtropical regions. They are responsible for the high temperatures and heat waves experienced in the western United States during the summer months.

Question 17

Drylines are most frequently observed in the western half of Texas, Oklahoma, and Kansas, especially during spring and early summer. In these locations, drylines tend to move eastward during the day, then westward toward evening.

Accepted Answer

Drylines, which are boundaries separating moist and dry air masses, are indeed most commonly observed in the western parts of Texas, Oklahoma, and Kansas, particularly in the spring and early summer. They typically move eastward during the day due to the heating of the land and then retreat westward in the evening as temperatures drop.

Question 18

Occluded fronts are often associated with a broad band of precipitation.

Accepted Answer

Occluded fronts occur when a cold front overtakes a warm front, lifting the warm air mass off the ground and leading to the formation of a broad band of precipitation as the warm air is cooled and condenses.

Question 19

The central United States is a very good air mass source region.

Accepted Answer

The central United States is not considered a very good air mass source region because it does not have the uniform characteristics typically associated with good source regions, such as vast, flat areas with consistent temperature and moisture levels. Good air mass source regions are usually large, flat areas with uniform surface characteristics, like the Arctic tundra, tropical oceans, or large deserts.

Question 20

Maritime tropical (mT)air masses are responsible for daily afternoon thunderstorms along the Gulf Coast.

Accepted Answer

Maritime tropical (mT) air masses are warm and moist, originating over warm ocean waters. When they move over land, such as the Gulf Coast, the warm, moist air can lead to the development of daily afternoon thunderstorms, especially in the summer.

Quiz 11: Air Masses and Fronts