Chapter 11 Questions for Review
If an area is described as a “good air mass source region”, what information can you
give about it?
A “good air mass source region” or “ideal source regions” are usually those areas
dominated by surface high pressure.
They include the ice and snow covered artic
plains in winter and subtropical oceans in summer.
It is summer.
What type of afternoon weather would you expect from an air mass
designated as mT?
In summer, the weather we could expect from mT air mass would be warm, moist
and usually unstable.
It would be warm because tropical (T) air masses form in a
warm tropical region.
It would be moist because maritime (m) air masses
originate over water.
Why is continental polar air not welcome to the Central Plains in winter and yet very
welcome in summer?
A summertime continental polar (cP) air is welcome in the Central Plains
because is usually brings relief from the oppressive heat in the central states as
cooler air lowers the air temperature to more comfortable levels.
however, a continental polar (cP) can bring bitter cold winter weather.
Explain why the central United States is not a good air mass source region.
The central United States is not a good air mass source region because it is
located in the middle latitude.
Middle latitudes, where surface temperatures and
moisture characteristics vary considerably, are not good source regions.
Why do air temperatures tend to be a little higher on the eastern side of the
Appalachian Mountains than on the western side, even though the same winter cP or
cA air mass dominates both areas?
Air rides up and over the lower Appalachian Mountains.
Turbulent mixing and
compressional heating increase the air temperatures on the downwind side.
Consequently, cities located to the east of the Appalachian Mountains usually do
not experience temperatures as low as those on the west side.
Explain how the airflow aloft regulates the movement of air masses.
Since the air mass itself is generally uniform with low winds, its movement is almost
entirely dictated by air movements aloft, which push on the air mass moving it around.
List the temperature and moisture characteristics of each of the major air mass types.
cA - Continental Artic - Extremely cold, dry stable; forms over an ice and snow-
cP - Continental Polar - cold, dry, stable
cT - Continental Tropical - hot, dry, stable air aloft; unstable surface air
mP - Maritime Polar - cool, moist, unstable
mT - warm, moist; usually unstable
What are lake-effect snows and how do they form? On which side of a lake do they typically
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