Flashcard Set Preview
Side ASide B
The two most important properties that should be relatively homogeneous at the same altitude in an are mass are...
moisture content and temperature
An air mass from the Gulf of Mexico is called:
An air mass from the Gulf of Mexico that moves northward over the U.S in winter would be labeled...
The air mass type most likely to form thunderstorms is...
In North America the ______ air mass forms only in the summer.
The pronounced cooling that occurs on continents at high latitudes during winter leads to the formation of ____ air masses.
An ideal source region of air masses should be...
An mP air mass is...
humid and cold
The cP air mass in North America originates in...
interior Alaska and Canada
Characteristics of an air mass source region include...
uniformity of temperature and moisture
The air masses that have the greatest influence on weather conditions in the Midwestern United States are...
cP and mT
An air mass source region...
is characterized by a general stagnation of atmospheric circulation
Why are cT air masses of minor importance for the U.S?
no large source region is near the U.S
The typical amount of time it takes for an air mass to pass over a given area is on the order of a few...
An air mass is often modified as it moves over the Earth's surface. This modification is largely due to
contact with the ground below
Air mass source regions are least likely to come from...
The coldest and driest winter air mass in North America is the...
Which of the following is not an air mass that influences North America?
Air mass source regions tend to be dominated by...
slow moving anticyclones
The ____ air mass often originates as a different air mass in Siberia and is subsequently altered.
Why are maritime air masses from the north Atlantic of only limited concern for weather in the U.S?
prevailing winds move them away from the U.S
The _____ air mass provides much of the moisture for precipitation in the central and eastern United States.
Which of the following occurs only in summer in North America?
Most of the precipitation for the region east of the Rocky Mountains comes from...
mT air masses
A cT air mass is...
warm and dry
Which of these is not a process by which air masses are modified?
"Lake-effect" snow is associated with the ____ air mass.
The ____ air mass may produce an occasional "northeaster" in the winter.
An air mass is a body of air with...
similar values of temperature and moisture in the horizontal
The stability of an air mass can be affected by...
a, b, and c
When an air mass is warmer than the surface over which it is moving...
the air becomes more stable
When an area is experiencing several consecutive days of rather constant weather, it is experiencing...
air mass weather